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	<title>Discrete Ideas &#187; The Count</title>
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	<description>Thoughts count</description>
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		<title>Fractured Memories</title>
		<link>http://www.discreteideas.com/2010/07/fraction-memorization/</link>
		<comments>http://www.discreteideas.com/2010/07/fraction-memorization/#comments</comments>
		<pubDate>Sun, 04 Jul 2010 04:12:12 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Learning]]></category>
		<category><![CDATA[math]]></category>
		<category><![CDATA[fractions]]></category>
		<category><![CDATA[learn]]></category>
		<category><![CDATA[repeating]]></category>
		<category><![CDATA[shortcut]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=306</guid>
		<description><![CDATA[
<p>Some fractions are a part of everyday life; dimes, quarters, nickels, hours, minutes, seconds, etc.  These are relatively easy to manage mainly because we deal with them so often.  Everyone just &#8220;knows&#8221; that 1/2 is 0.5, and 1/4 is .25, and 1/10 is 0.1; we&#8217;ve had it ingrained in us through massive amounts of [...]]]></description>
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<p><img src="/art/numbers/memory.jpg" class="inline_pic left_pic" />Some fractions are a part of everyday life; dimes, quarters, nickels, hours, minutes, seconds, etc.  These are relatively easy to manage mainly because we deal with them so often.  Everyone just &#8220;knows&#8221; that 1/2 is 0.5, and 1/4 is .25, and 1/10 is 0.1; we&#8217;ve had it ingrained in us through massive amounts of repetition.  I go one step further; I can usually estimate the decimal equivalent of just about any fraction that comes up in my life.  Super useful?  Maybe not, but it has good show-off value, and I think it&#8217;s fun!<br clear="all" /><br />
<span id="more-306"></span></p>
<p>Learning the first 12 fractions can make it super-easy to do division in your head and produce answers down to the 10ths or even 1000ths quickly and easily.  Let&#8217;s take a look:</p>
<table>
<thead>
<td width="8%">Denominator</td>
<td width="25%">Values</td>
<td>Tips</td>
</thead>
<tr>
<td>1/1</td>
<td>1</td>
<td>This is the easy one, put here for completeness.  It could be beneficial to remember that any non-zero number N over N = N/N = 1.</td>
</tr>
<tr>
<td>1/2</td>
<td>1/2 = 0.5</td>
<td>Sure, it&#8217;s simple, but it&#8217;s useful when trying to compute 1/20th, etc.</td>
</tr>
<tr>
<td>1/3</td>
<td>
			1/3 = 0.333*<br />
			2/3 = 0.666*
		</td>
<td>That&#8217;s 0.333*, where the 3s never stop, also called 0.3 <i>repeating</i>.  And yes, 0.9 repeating <i>does</i> <a href="http://www.discreteideas.com/2010/05/mom-was-right-repeating-9/">equal 1</a>!</td>
</tr>
<tr>
<td>1/4</td>
<td>
			1/4 = 0.25<br />
			2/4 = 0.5<br />
			3/4 = 0.75
		</td>
<td>Here&#8217;s the first one where just memorizing keeps you from having to reduce 2/4 = 1/2.</td>
</tr>
<tr>
<td>1/5</td>
<td>
			1/5 = 0.2<br />
			2/5 = 0.4<br />
			3/5 = 0.6<br />
			4/5 = 0.8
		</td>
<td>N/5 = 0.(2*N).  Note you&#8217;re really multiplying N by 2, then dividing by 10 (which just moves the decimal):  3/5 = (3*2)/10 = 0.6!</td>
</tr>
<tr>
<td>1/6</td>
<td>
			1/6 = 0.1666*<br />
			2/6 = 0.3333*<br />
			3/6 = 0.5<br />
			4/6 = 0.6666*<br />
			5/6 = 0.8333*
		</td>
<td>Ok, this one&#8217;s not so simple.  It helps to realize that 0.333* / 2 = 0.1666*, and go from there.  Having 3/6 = 0.5 in the middle can help too, since 5/6 = 3/6 + 2/6 = 0.5 + 0.333* = 0.833*, see?</td>
</tr>
<tr>
<td>1/7</td>
<td>
			1/7 = 0.142857*<br />
			2/7 = 0.285714*<br />
			3/7 = 0.428571*<br />
			4/7 = 0.571428*<br />
			5/7 = 0.714285*<br />
			6/7 = 0.857142*
		</td>
<td>This is by far my favorite fraction.  Note that in all cases, all <b>six</b> digits repeat, so 1/7 = 0.142857142857&#8230;  Also note that the same six digits appear in the same order for all 6 fractions, you just start with a different digit.  I use the fact that 14 is half 28 is half (just about) 57 to help remember the digits, too.  This is the impressive one, guys.  Someone asks, &#8220;what&#8217;s 1/7th of 100?&#8221; and you say &#8220;14.2857&#8243; instantly.  Nice.</td>
</tr>
<tr>
<td>1/8</td>
<td>
			1/8 = 0.125<br />
			2/8 = 0.25<br />
			3/8 = 0.375<br />
			4/8 = 0.5<br />
			5/8 = 0.625<br />
			6/8 = 0.75<br />
			7/8 = 0.875
		</td>
<td>Seems like a lot to know, but most are easily computable from knowing 1/8 and reducing the rest.  5/8 = 4/8 + 1/8 = 0.5 + 0.125 = 0.625</td>
</tr>
<tr>
<td>1/9</td>
<td>
			1/9 = 0.111*<br />
			2/9 = 0.222*<br />
			&#8230;<br />
			7/9 = 0.777*<br />
			8/9 = 0.888*
		</td>
<td>Just take the numerator and repeat it over and over.  And again, 9/9 = 0.999* = 1.  Also of note, any number N (up to 99) over 99 0.N* too, but use both digits, so 5/99 = 0.050505*, 63/99 = 0.636363*, etc.  This continues for 999, 9999, etc.</td>
</tr>
<tr>
<td>1/10</td>
<td>
			1/10 = 0.1<br />
			2/10 = 0.2<br />
			&#8230;<br />
			8/10 = 0.8<br />
			9/10 = 0.9
		</td>
<td>These are pretty self-evident.  You&#8217;re dividing by 10, so just slide the decimal place.</td>
</tr>
<tr>
<td>1/11</td>
<td>
			1/11 = 0.0909*<br />
			2/11 = 0.1818*<br />
			3/11 = 0.2727*<br />
			4/11 = 0.3636*<br />
			5/11 = 0.4545*<br />
			6/11 = 0.5454*<br />
			7/11 = 0.6363*<br />
			8/11 = 0.7272*<br />
			9/11 = 0.8181*<br />
			10/11 = 0.9090*
		</td>
<td>See what&#8217;s happening?   N/11 = 0.(N*9) repeating, with both digits repeating (Note, 1*9 = 09 in this case).  This becomes obvious when you think that 11/11 must equal 0.9999*, so dividing that by 11 must divide each of those 99s in the decimal by 11 as well: 0.9999* / 11 = 0.0909*. </td>
</tr>
<tr>
<td>1/12</td>
<td>
			1/12 = 0.0833*<br />
			2/12 = 0.1666*<br />
			3/12 = 0.25*<br />
			4/12 = 0.3333*<br />
			5/12 = 0.4166*<br />
			6/12 = 0.5<br />
			7/12 = 0.5833*<br />
			8/12 = 0.6666*<br />
			9/12 = 0.75<br />
			10/12 = 0.8333*<br />
			11/12 = 0.9166*
		</td>
<td>I must admit, I don&#8217;t really have these memorized.  I know that 1/12 = 0.833* and work from there.  7/12 = 6/12 + 1/12 = 0.5 + 0.0833* = 0.5833*, etc.  Since half the values for N reduce to smaller fractions, this is where I leave off memorizing.</td>
</tr>
</table>
<p><img src="/art/numbers/fractions.jpg" class="inline_pic right_pic" />There you have them, the first 12 fractions for easy memorization.  Amaze your friends!  Astound your kids!  Become even more of a know-it-all than you already are!  I joke, but I guess you&#8217;d be surprised how often I use these, I know I am.<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
<br clear="all" /></p>
<hr width="66%"/>
<font size="-1">P.S. Please excuse my use of * to denote repeating decimals, I&#8217;d be happy to hear of a better symbol, since my font doesn&#8217;t allow lines across the top of text</font><br />
<br clear="all" /></p>
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		<item>
		<title>Elegance in motion</title>
		<link>http://www.discreteideas.com/2010/05/elegance-in-motion/</link>
		<comments>http://www.discreteideas.com/2010/05/elegance-in-motion/#comments</comments>
		<pubDate>Thu, 27 May 2010 04:41:54 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Fun]]></category>
		<category><![CDATA[Repost]]></category>
		<category><![CDATA[math]]></category>
		<category><![CDATA[autotune]]></category>
		<category><![CDATA[video]]></category>
		<category><![CDATA[youtube]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=295</guid>
		<description><![CDATA[
<p>Every once in awhile, I come across a video (usually on Youtube, isn&#8217;t that where everthing ends up) that quite elegantly illustrates something math-related.  I haven&#8217;t been collecting them long, but I thought I&#8217;d share a couple of them with you all.  Please enjoy them as much as I have.



Autotuning is a relatively recent [...]]]></description>
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<p><img src="/art/special/movies.jpg" class="inline_pic left_pic" />Every once in awhile, I come across a video (usually on Youtube, isn&#8217;t that where everthing ends up) that quite elegantly illustrates something math-related.  I haven&#8217;t been collecting them long, but I thought I&#8217;d share a couple of them with you all.  Please enjoy them as much as I have.<br clear="all" /><br />
<span id="more-295"></span><br />
<center>
<div style="background-color: #69b6cf; width: 800px; padding: 10px;">
Autotuning is a relatively recent fad in the music industry which has everything to do with the mathematics of sound.  How else can they take someone&#8217;s speaking voice and make them sing!?<br />
<center><br />
<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/zSgiXGELjbc&#038;hl=en_US&#038;fs=1&#038;rel=0&#038;color1=0x2b405b&#038;color2=0x6b8ab6"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/zSgiXGELjbc&#038;hl=en_US&#038;fs=1&#038;rel=0&#038;color1=0x2b405b&#038;color2=0x6b8ab6" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object><br />
</center>
</div>
<p></center><br />
<br clear="all" /><br />
<center>
<div style="background-color: #69b6cf; width: 800px; padding: 10px;">
This is a quite brilliant video showing how mathematics is present in the shapes of nature.  I find it amazing that such &#8220;irrational&#8221; numbers come from naturally occurring phenomena.<br />
<center><br />
<object width="560" height="340"><param name="movie" value="http://www.youtube.com/v/kkGeOWYOFoA&#038;hl=en_US&#038;fs=1&#038;rel=0&#038;color1=0x2b405b&#038;color2=0x6b8ab6&#038;hd=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/kkGeOWYOFoA&#038;hl=en_US&#038;fs=1&#038;rel=0&#038;color1=0x2b405b&#038;color2=0x6b8ab6&#038;hd=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="560" height="340"></embed></object><br />
</center>
</div>
<p></center><br />
<br clear="all" /><br />
<img src="/art/special/spirals.jpg" class="inline_pic right_pic" />There you have it.  I hope you enjoyed those videos.  I have a few more, but I think I&#8217;ll save them for later.  You probably have to get back to work, or some equally non-Math-related thing.  Sorry about that; I&#8217;ll be back to distract again later.<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
<br clear="all" /></p>
]]></content:encoded>
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		</item>
		<item>
		<title>Mom was right</title>
		<link>http://www.discreteideas.com/2010/05/mom-was-right-repeating-9/</link>
		<comments>http://www.discreteideas.com/2010/05/mom-was-right-repeating-9/#comments</comments>
		<pubDate>Sun, 09 May 2010 14:00:44 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Learning]]></category>
		<category><![CDATA[Proofs]]></category>
		<category><![CDATA[math]]></category>
		<category><![CDATA[Mother]]></category>
		<category><![CDATA[proof]]></category>
		<category><![CDATA[repeating]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=279</guid>
		<description><![CDATA[
<p>Ah, Mother&#8217;s Day.   Admittedly, Math isn&#8217;t the first thing you think about when scrambling for that 1-800-Flowers phone number (I always forget that one) or that last box of chocolate from the drugstore.  However, one of the memories that sticks in my mind most about my Mom is arguing with her about Math [...]]]></description>
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<p><img src="/art/numbers/argument.jpg" class="inline_pic left_pic" />Ah, Mother&#8217;s Day.   Admittedly, Math isn&#8217;t the first thing you think about when scrambling for that 1-800-Flowers phone number (I always forget that one) or that last box of chocolate from the drugstore.  However, one of the memories that sticks in my mind most about my Mom is arguing with her about Math during dinner about .9 repeating and 1.  Before you think we&#8217;re crazy, please keep in mind she&#8217;s a Math teacher, and I have some small interest in the subject myself.  So here&#8217;s to you, Mom.  I finally realized you were right some time ago, but don&#8217;t think I ever said so.<br clear="all" /><br />
<span id="more-279"></span><br />
I didn&#8217;t really have any good arguments for my side of the case.  What can I say?  I was 8 or 9 and saying things like &#8220;1 minus 0.9 repeating is 0.0 repeating with a 1 at the end&#8221; made perfect sense to me.  I also have to say I didn&#8217;t listen that much to Mom&#8217;s arguments, so I&#8217;m not sure she used these following proofs, but I&#8217;m pretty sure they should convince just about anyone.<br clear="all" /><br />
First, there&#8217;s simple addition.  If you agree that 1/3 = 0.3333(repeating), then:<br clear="all" /><br />
<center></p>
<table style="margin: 6px;">
<tr>
<td>Start with 1/3rd</td>
<td style="text-align: right; padding-right: 10px;"> 1 / 3 = </td>
<td> 0.33333333&#8230;</td>
</tr>
<tr>
<td>Add another 1/3rd</td>
<td style="text-align: right; padding-right: 10px;"> 2 / 3 = </td>
<td> 0.66666666&#8230;</td>
</tr>
<tr>
<td>Add a final 1/3rd</td>
<td style="text-align: right; padding-right: 10px;"> 3 / 3 = 1 = </td>
<td> 0.99999999&#8230;</td>
</tr>
</table>
<p></center><br />
Ok, what about the algebraic solution?<br clear="all" /><br />
<center></p>
<table style="margin: 6px;">
<tr>
<td> Start with:  </td>
<td style="text-align: right; padding-right: 10px;"> X = </td>
<td> 0.99999999&#8230;</td>
</tr>
<tr>
<td> Multiply both sides by 10:  </td>
<td style="text-align: right; padding-right: 10px;"> 10X = </td>
<td> 9.99999999&#8230;</td>
</tr>
<tr>
<td> Subtract the first row from the second:  </td>
<td style="text-align: right; padding-right: 10px;"> 9X = </td>
<td> 9</td>
</tr>
<tr>
<td> Now divide both sides by 9:  </td>
<td style="text-align: right; padding-right: 10px;"> X = </td>
<td> 1</td>
</tr>
</table>
<p></center><br />
See how we started with X = 0.999999&#8230; and ended with X = 1? That means they&#8217;re the same!<br clear="all" /><br />
Finally, there is the infinite geometric series, where each term is a set ratio of the previous term.  In the case of 0.99999&#8230;, we can say that this is the sum of 0.9 + 0.09 + 0.009&#8230; This gives us an initial term of 0.9, and a ratio between terms of 1/10.<br />
<center></p>
<table style="margin: 6px;">
<tr>
<td width="60%"> Geometric series sum is this formula, where A is the initial term, and R is the ratio between terms:  </td>
<td width="40%" style="text-align: center"> S = A(1-(R^N)) / (1-R) </td>
</tr>
<tr>
<td> Since we want N to be infinite (the 9&#8242;s do go on forever) and |R| < 1, then R^N becomes 0:  </td>
<td style="text-align: center"> S = A(1 &#8211; 0) / (1 &#8211; R)</td>
</tr>
<tr>
<td> The initial term in the series A is 0.9, and the ratio between terms R is 0.1 </td>
<td style="text-align: center"> S = 0.9(1) / (1 &#8211; 0.1)</td>
</tr>
<tr>
<td> Algebra time, see how the series sum becomes 1?  </td>
<td style="text-align: center"> S = 0.9 / 0.9 = 1</td>
</tr>
</table>
<p></center><br />
<img src="/art/numbers/repeating9.jpg" class="inline_pic right_pic" />I admit, that last one wouldn&#8217;t have made much sense to me at 9 years old. It just goes to show how many different ways you can prove that 0.9(repeating) is the same as 1.  I hope my Mom reads this and realizes that it&#8217;s finally sunken into my brain that she was right&#8230; on at least this <i>one</i> occasion.  If you ever lose an argument with your Mom, make sure you let her know about it, too.  Happy Mother&#8217;s Day to you all.<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
<br clear="all" /></p>
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		<title>Tax Bracketology</title>
		<link>http://www.discreteideas.com/2010/04/tax-bracketology/</link>
		<comments>http://www.discreteideas.com/2010/04/tax-bracketology/#comments</comments>
		<pubDate>Wed, 14 Apr 2010 14:00:44 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Stats]]></category>
		<category><![CDATA[money]]></category>
		<category><![CDATA[history]]></category>
		<category><![CDATA[taxes]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=273</guid>
		<description><![CDATA[A graphical look at tax burdens based on income and spread across multiple year's worth of tax tables. [...]]]></description>
			<content:encoded><![CDATA[<style>
li { padding-bottom: 3px; }
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<p><img src="/art/numbers/money.jpg" class="inline_pic left_pic" />Now, how could the Count pass up a chance to talk about that most numerically significant time of year, Tax Time!?  With lots of talk about rising tax rates and socialism this year, I thought it might be fun and informative to take a look at tax tables from previous years and compare them to recent times.  <br clear="all" /><br />
<span id="more-273"></span>Using a spreadsheet I found on the internet<span class="link_id">1</span>, I created a table of tax burdens by year for different income levels.  While the tax brackets have seen highs in the 90s percent in the post-war 40s and 50s, and started with lows of 1-7% in the early 1910s, I figured 1970 was a good starting point for modern relevancy. I further pared this information down to just the years after fairly significant changes to the tax codes, as many of the annual lines were very similar.  I also chose to use the Married Filing Singly tax table, as it was most often the same as Single, and almost always half the income amounts of Married Filing Jointly for the same tax.  Here&#8217;s is the resulting data:<br clear="all" /><br />
<center><img src="/art/numbers/taxes.png" /></center><br clear="all" /><br />
Of note:</p>
<ul>
<li>The percentage tax burden isn&#8217;t the tax &#8220;bracket&#8221;, it&#8217;s the total amount paid in taxes if your income was at the displayed level.  Of course, tax shelters exist, but this is based on &#8220;taxable income&#8221;, the number you use when you look up how much tax you owe.</li>
<li>Quite obviously, the 1970s were not a good time to be making money.  Yes, home interest rates were in the teens, so anyone who owned a home had quite a nice write-off in the interest they were paying, but good Lord, that&#8217;s some high taxes!</li>
<li>1988 was a good year to make a lot of money, where people making $100k actually paid a (slightly) higher percentage of their income in taxes than those making 3 or even 5 times as much!</li>
</ul>
<p>Finally, I notice that only at 1993 do we see a marked rise in taxes, and only for those making $100k or more; it seems that taxes have done nothing but drop since 1970 except for that one year.  Of course, things like the Alternative Minimum Tax and changes to Capital Gains taxes change the landscape, making it very difficult to get a clear picture of true tax liabilities.<br clear="all" /><br />
<img src="/art/numbers/forms.jpg" class="inline_pic right_pic" />This is quite interesting!  People are never happy paying taxes, but I think it&#8217;s refreshing to see we&#8217;ve got it quite lucky nowadays compared to our parents, tax-wise.  Now, if only we could get that money spent just the way we want it, no?  But that&#8217;s another topic.  I sense a post about unusual budget items!  Look for it in the future; right now, I&#8217;ve got to go file my taxes.<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
<br clear="all" /></p>
<ol>
<li><a href="http://www.taxfoundation.org/publications/show/151.html">Historical US Tax Tables</a></li>
</ol>
<p><br clear="all" /><br />
Interested in the data I compiled for the above chart?  Here it is:<br clear="all" /></p>
<table>
<thead>
<td>Income /<br/>Year	</td>
<td>$20,000.00	</td>
<td>$50,000.00	</td>
<td>$80,000.00	</td>
<td>$120,000.00	</td>
<td>$200,000.00	</td>
<td>$350,000.00	</td>
<td>$500,000.00</td>
</thead>
<tr>
<td>1970	</td>
<td>$6,070.00	</td>
<td>$22,590.00	</td>
<td>$41,790.00	</td>
<td>$69,490.00	</td>
<td>$125,490.00	</td>
<td>$230,490.00	</td>
<td>$335,490.00</td>
</tr>
<tr>
<td>1981	</td>
<td>$5,113.00	</td>
<td>$20,999.00	</td>
<td>$39,964.00	</td>
<td>$67,362.00	</td>
<td>$123,362.00	</td>
<td>$228,362.00	</td>
<td>$333,362.00</td>
</tr>
<tr>
<td>1982	</td>
<td>$4,597.50	</td>
<td>$18,724.50	</td>
<td>$33,724.50	</td>
<td>$53,724.50	</td>
<td>$93,724.50	</td>
<td>$168,724.50	</td>
<td>$243,724.50</td>
</tr>
<tr>
<td>1986	</td>
<td>$3,717.55	</td>
<td>$15,701.50	</td>
<td>$30,040.50	</td>
<td>$49,964.25	</td>
<td>$89,964.25	</td>
<td>$164,964.25	</td>
<td>$239,964.25</td>
</tr>
<tr>
<td>1988(a)	</td>
<td>$3,666.25	</td>
<td>$12,768.75	</td>
<td>$22,668.75	</td>
<td>$35,533.75	</td>
<td>$57,933.75	</td>
<td>$99,933.75	</td>
<td>$141,933.75</td>
</tr>
<tr>
<td>1992	</td>
<td>$3,273.00	</td>
<td>$11,875.50	</td>
<td>$21,175.50	</td>
<td>$33,575.50	</td>
<td>$58,375.50	</td>
<td>$104,875.50	</td>
<td>$151,375.50</td>
</tr>
<tr>
<td>1993	</td>
<td>$3,201.50	</td>
<td>$11,764.25	</td>
<td>$21,564.25	</td>
<td>$35,964.25	</td>
<td>$67,464.25	</td>
<td>$126,864.25	</td>
<td>$186,264.25</td>
</tr>
<tr>
<td>2000	</td>
<td>$3,000.00	</td>
<td>$11,149.75	</td>
<td>$20,360.50	</td>
<td>$34,724.25	</td>
<td>$65,533.95	</td>
<td>$124,933.95	</td>
<td>$184,333.95</td>
</tr>
<tr>
<td>2003	</td>
<td>$2,650.00	</td>
<td>$9,777.50	</td>
<td>$17,957.75	</td>
<td>$30,790.25	</td>
<td>$58,070.75	</td>
<td>$110,570.75	</td>
<td>$163,070.75</td>
</tr>
<tr>
<td>2010	</td>
<td>$2,581.25	</td>
<td>$8,681.25	</td>
<td>$16,521.75	</td>
<td>$28,490.50	</td>
<td>$55,154.00	</td>
<td>$107,654.00	</td>
<td>$160,154.00</td>
</tr>
</table>
]]></content:encoded>
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		<slash:comments>1</slash:comments>
		</item>
		<item>
		<title>Pi for lunch?</title>
		<link>http://www.discreteideas.com/2010/03/pi-for-lunch/</link>
		<comments>http://www.discreteideas.com/2010/03/pi-for-lunch/#comments</comments>
		<pubDate>Sun, 14 Mar 2010 19:18:23 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Fun]]></category>
		<category><![CDATA[Humor]]></category>
		<category><![CDATA[math]]></category>
		<category><![CDATA[geek]]></category>
		<category><![CDATA[holiday]]></category>
		<category><![CDATA[Pi]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=270</guid>
		<description><![CDATA[
<p>Happy Pi Day!  Yes, it&#8217;s that time of year again when the month and day (in the American form of date representation) for those legendary 3 digits 3/14, also known as the beginning of the mathematical term Pi1.  Being The Count, however, I&#8217;m certainly not satisfied with just one Pi Day each year, or [...]]]></description>
			<content:encoded><![CDATA[<style>
</style>
<p><img src="/art/teach/calendar.jpg" class="inline_pic left_pic" />Happy Pi Day!  Yes, it&#8217;s that time of year again when the month and day (in the American form of date representation) for those legendary 3 digits 3/14, also known as the beginning of the mathematical term Pi<span class="link_id">1</span>.  Being The Count, however, I&#8217;m certainly not satisfied with just one Pi Day each year, or just matching 3 digits of Pi for my festivities.  No, I must venture forth to find other Math-related dates to share the joy that is the geeky holiday.<br clear="all" /><br />
<span id="more-270"></span><br />
Now, Pi Day comes every year but only in America, as the European version of date display comes Day then Month.  Unfortunately, this leaves Europe with no way to put forth 3.14 (note, they use a period (.) instead of a slash (/)), as alas, there are only 12 months.  For the most part, Europe seems to be out of luck.  After searching  several dozen math constants<span class="link_id">2</span>, and I can&#8217;t find any that start with a number from 1-30, and have 2 digits after the decimal that form a number less than 13.  Viswanath&#8217;s Constant<span class="link_id">3</span> comes closest, but it looks like we&#8217;ll just have to exclude Europeans from our celbratory antics&#8230; No pie for you!<br clear="all" /><br />
Not so fast!  Let&#8217;s try not to leave them out of all the fun.  I present below some alternatives to Pi day, some of which can even be translated to Day before Month!</p>
<table>
<thead>
<td>Date</td>
<td>Reason</td>
<td>Name</td>
<td>Celebration</td>
</thead>
</tr>
<td>3/14/15</td>
<td>Pi</td>
<td>Super Pi Day</td>
<td>Eat <i>nothing</i> but pie all day.  Luckily, there are many, many varieties<span class="link_id">4</span></td>
</tr>
</tr>
<td>11/23/58</td>
<td><a href="http://en.wikipedia.org/wiki/Fibonacci_number">Fibonacci Sequence</a></td>
<td>Fibonacci Day</td>
<td>Every hour, give a gift that costs as much as the last two gifts, starting with 2 $1 gifts. (20 points to whomever figures how much the last gift costs)</td>
</tr>
</tr>
<td>1/6/18</td>
<td><a href="http://en.wikipedia.org/wiki/The_Golden_Ratio">Phi</a></td>
<td>Golden Ratio Day</td>
<td>Do unto others only what you&#8217;d want to do to you, 1.618 as much!</td>
</tr>
</tr>
<td>2/7/18</td>
<td><a href="http://en.wikipedia.org/wiki/Euler%27s_Number">e</a></td>
<td>Euler&#8217;s Number Day</td>
<td>Do something that people used to believe was impossible.<span class="link_id">5</span></td>
</tr>
</table>
<p><br clear="all" /><br />
<img src="/art/teach/pipie.jpg" class="inline_pic right_pic" />We&#8217;ll have to wait a bit for these extra-geeky days to arrive, but at least we have today!  So, those of you who <b>can</b> celebrate Pi day, run out to your Marie Callander&#8217;s or Coco&#8217;s, or even the local Denny&#8217;s, grab a slice, and enjoy!  Save some room for Super Pi Day in a few years though, ok?<br clear="all" /><br />
<span class="count_sign">The Count</span></p>
<hr width="66%"/>
<ol>
<li><a href="http://en.wikipedia.org/wiki/Pi">Pi</a> &#8211; the math constant, not the pastry</li>
<li><a href="http://en.wikipedia.org/wiki/Mathematical_constant">Math Constants</a></li>
<li><a href="http://en.wikipedia.org/wiki/Viswanath%27s_constant">Viswanath&#8217;s Constant</a></li>
<li><a href="http://quizme.stvlive.com/pie/quiz.php">What kind of pie are you?
<li><a href="http://xkcd.com/179/">XKCD on e and Pi</a></li>
</ol>
]]></content:encoded>
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		</item>
		<item>
		<title>The Gift of Years</title>
		<link>http://www.discreteideas.com/2010/01/the-gift-of-years/</link>
		<comments>http://www.discreteideas.com/2010/01/the-gift-of-years/#comments</comments>
		<pubDate>Sat, 30 Jan 2010 21:30:26 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Fun]]></category>
		<category><![CDATA[Stats]]></category>
		<category><![CDATA[application]]></category>
		<category><![CDATA[birthday]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=263</guid>
		<description><![CDATA[
<p>What?!  Another birthday so soon!?  No, you haven&#8217;t lost 6 months of your life, and The Count isn&#8217;t 41&#8230; yet!  Due to the overwhelming popularity of my Birthday article, it became clear to me that even those people that weren&#8217;t born during the awesome year of 1969 would like to be able to [...]]]></description>
			<content:encoded><![CDATA[<style>
</style>
<p><img src="/art/birthday/colors.jpg" class="inline_pic left_pic" />What?!  Another birthday so soon!?  No, you haven&#8217;t lost 6 months of your life, and The Count isn&#8217;t 41&#8230; yet!  Due to the overwhelming popularity of my <a href="http://www.discreteideas.com/2009/09/counting-time/">Birthday article</a>, it became clear to me that even those people that weren&#8217;t born during the awesome year of 1969 would like to be able to see their own age in huge-numbered detail.<br clear="all" /><br />
<span id="more-263"></span><br />
After many hours of toil, The Count has made available to you, his loyal reader, a page designed to give you all the joy he felt in seeing his age in Earth years converted to galactically-large numbers of other units.  Simply click the link below, and enjoy!</p>
<p><center><a style="font-size:14px" href="http://www.discreteideas.com/age-converter/">The Count&#8217;s Age Converter</a></center></p>
<p><span class="count_sign">The Count</span></p>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>A Hard Lesson Learned</title>
		<link>http://www.discreteideas.com/2009/12/a-hard-lesson-learned/</link>
		<comments>http://www.discreteideas.com/2009/12/a-hard-lesson-learned/#comments</comments>
		<pubDate>Sun, 13 Dec 2009 06:52:39 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Stats]]></category>
		<category><![CDATA[math]]></category>
		<category><![CDATA[dice]]></category>
		<category><![CDATA[statistics]]></category>
		<category><![CDATA[transform]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=222</guid>
		<description><![CDATA[
<p>Have you ever had a problem stuck in your head, and you couldn&#8217;t find the answer?  I was recently reminded of a problem I first came up with while doing a statistics workbook the summer of my 3rd grade year (yes, my math-teacher mother gave us workbooks to do during summer break&#8230; hey, it got [...]]]></description>
			<content:encoded><![CDATA[<style>
</style>
<p><img src="/art/lotto/qmark.jpg" class="inline_pic left_pic" />Have you ever had a problem stuck in your head, and you couldn&#8217;t find the answer?  I was recently reminded of a problem I first came up with while doing a statistics workbook the summer of my 3rd grade year (yes, my math-teacher mother gave us workbooks to do during summer break&#8230; hey, it got results).  The book dealt with dice and the probabilities of a 1 showing on a 6-sider, or the sum of 2 rolled dice being 7, etc. but my question had a twist I couldn&#8217;t quite solve.  Now it&#8217;s easy to see that the probability of rolling a 1 on a 6-sided die is 1 in 6, but what probability exists, in rolling 2 dice, of seeing at least one 1 (on either die, or both)?<br clear="all" /><br />
<span id="more-222"></span><br />
So there I was, 7 years old and stuck with a math problem I couldn&#8217;t solve.  Well, what would <i>you</i> do?  That&#8217;s right, I asked people.  Over the next 9 years, I asked math teachers and other adults I thought might be able to help, but no one seemed able to explain it to me.  Of course, I could brute force the answer for 2 or even 3 dice quite easily as well (and did), but by that time I wasn&#8217;t interested in just the single answer to my problem, but a more general solution for N dice.  The difficulty of the problem comes from the &#8220;at least one&#8221; phrasing.  Using discrete math, you could end up having to compute the probability for each of the numbers of dice smaller than your requested count and use alternating subtraction and addition to account for subset solutions and overlap.<br clear="all" /><br />
Of course, I did come up with (or was given) attempts at a quicker solution.  They usually fell into 2 types.  The first type was the simplest; since we were rolling two dice, and the probability with 1 die was 1 in 6, the new probability must be 2 in 6.  Unfortunately, this easily extrapolates to say that when rolling 6 dice, you absolutely must get a 1, 2, 3, 4, 5, and 6.  Anyone who plays Yahtzee can certainly see the flaw there.  The second type of false solution came from, at some point, someone recalling some remnant of a college statistics course (the part where previous rolls shouldn&#8217;t affect subsequent rolls) and concluding that the answer must be still 1 in 6.  This answer also fails to satisfy quickly when you consider more than just 2 dice being rolled.  How could the probability of getting at least one 1 when rolling 10 or even 100 dice still be just 1 in 6?<br clear="all" /><br />
It wasn&#8217;t until I reached college and took an actual course in statistics that I found the answer.  Fortunately, there&#8217;s an easy method.  If you ever find a statistics problem that uses the &#8220;at least one&#8221; phrase, the best bet is to turn it around.  What are the odds of <b>not</b> getting <b>any</b> 1s on those dice?  As it happens, that&#8217;s merely 5 in 6 for each die rolled, multiplied together.  In my problem, with only 2 dice, the probability of not getting a 1 is 5/6 * 5/6 = or 25 in 36.  Now, since all the <b>other</b> possible results must contain a 1, we&#8217;re left with a solution of (36-25) = 11 in 36!  This method works for N dice as well, with the probability of getting at least one 1 out of N dice rolled being:<br clear="all" /><br />
<center><span style="font-size:16px;">P(N) = 1 &#8211; (5/6)^N.</span></center><br />
<br clear="all" /><br />
<img src="/art/lotto/dice.jpg" class="inline_pic right_pic" />Imagine that, all this time I&#8217;d been asking relatively smart people for the answer to a question I&#8217;d found a long time ago and the trick wasn&#8217;t really in finding the solution, but in re-wording the question so the solution became obvious.  This is a lesson every math student will learn along the way.  I wish I could go back and tell my 7-year-old self how easy it was to solve, without him having to see how hard it was to find the answer.<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
<br clear="all" /><br clear="all" /></p>
]]></content:encoded>
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		<item>
		<title>Streaking surprise</title>
		<link>http://www.discreteideas.com/2009/11/streaking-surprise/</link>
		<comments>http://www.discreteideas.com/2009/11/streaking-surprise/#comments</comments>
		<pubDate>Thu, 26 Nov 2009 18:44:38 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Sports]]></category>
		<category><![CDATA[Stats]]></category>
		<category><![CDATA[football]]></category>
		<category><![CDATA[NFL]]></category>
		<category><![CDATA[streak]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=200</guid>
		<description><![CDATA[td.cent { text-align: center; }

<p>I&#8217;m a football fan&#8230; well, more specifically the NFL.   I hear that colleges other than the one I went to actually have their own teams and that quite a lot of people think that the outcomes of these &#8220;college football games&#8221; are important, but I never saw the appeal.  [...]]]></description>
			<content:encoded><![CDATA[<style>
td.cent { text-align: center; }
</style>
<p><img src="/art/sports/football.jpg" class="inline_pic left_pic" />I&#8217;m a football fan&#8230; well, more specifically the NFL.   I hear that colleges other than the one I went to actually have their own teams and that quite a lot of people think that the outcomes of these &#8220;college football games&#8221; are important, but I never saw the appeal.  Anyway, as I said, I follow the NFL.  This year, as the season has proceeded, I&#8217;ve found myself noticing quite a few long winning and losing streaks occuring this year.  With 2 teams reaching 10-0, and a few teams having streaks of 6 and 7 wins (or losses), I decided to track the actual numbers and determine just how abnormal this season is.<br clear="all" /><br />
<span id="more-200"></span>Using one of the many available NFL statistic sites, I was able to compile the number of streaks that occured at each of the 10 lengths available at week 11 (which was just completed).  Note that only 10 games have been played by each team at this point, and that I ignored the bye week, allowing streaks to continue through the bye uninterrupted.  The following are my results:<br clear="all" /><br />
<center></p>
<table width="520">
<tr>
<td width="170">Streak Length</td>
<td style="text-align:center" width="35">1</td>
<td style="text-align:center" width="35">2</td>
<td style="text-align:center" width="35">3</td>
<td style="text-align:center" width="35">4</td>
<td style="text-align:center" width="35">5</td>
<td style="text-align:center" width="35">6</td>
<td style="text-align:center" width="35">7</td>
<td style="text-align:center" width="35">8</td>
<td style="text-align:center" width="35">9</td>
<td style="text-align:center" width="35">10</td>
</tr>
<tr>
<td style="text-align:left">Streak Count</td>
<td style="text-align:center">79</td>
<td style="text-align:center">30</td>
<td style="text-align:center">22</td>
<td style="text-align:center">8</td>
<td style="text-align:center">5</td>
<td style="text-align:center">4</td>
<td style="text-align:center">2</td>
<td style="text-align:center">0</td>
<td style="text-align:center">0</td>
<td style="text-align:center">2</td>
</tr>
</table>
<p></center><br />
Now, to determine how abnormal this year is (so far), I first have to determine what the expected count for each of the streak lengths is.  I must admit, I had to seek outside help determining what this should be, as my first few attempts bore rotten fruit.  Luckily, there are some helpful folks at <a href="www.mathoverflow.com">MathOverflow</a>, one of which was able to find a <a href="http://mathoverflow.net/questions/6929/chances-of-streaks-in-small-bit-streams">solution</a>:<br clear="all" /><br />
<center></p>
<table width="560">
<tr>
<td width="190">Streak Length</td>
<td style="text-align:center" width="35">1</td>
<td style="text-align:center" width="35">2</td>
<td style="text-align:center" width="35">3</td>
<td style="text-align:center" width="35">4</td>
<td style="text-align:center" width="35">5</td>
<td style="text-align:center" width="35">6</td>
<td style="text-align:center" width="35">7</td>
<td style="text-align:center" width="35">8</td>
<td style="text-align:center" width="35">9</td>
<td style="text-align:center" width="35">10</td>
</tr>
<tr>
<td>Streak Count</td>
<td style="text-align:center">96</td>
<td style="text-align:center">44</td>
<td style="text-align:center">20</td>
<td style="text-align:center">9</td>
<td style="text-align:center">4</td>
<td style="text-align:center">1.75</td>
<td style="text-align:center">0.75</td>
<td style="text-align:center">0.31</td>
<td style="text-align:center">0.13</td>
<td style="text-align:center">0.06</td>
</tr>
<tr>
<td colspan="11" style="font-size:10px;">
I know, these numbers seem small, given that I&#8217;d expect HALF of the 2-game sequences to be a 2-game streak.  The trick here is know that every 3-game streak has two 2-game streaks inside it which don&#8217;t count!
</td>
</tr>
</table>
<p></center><br />
Now, let&#8217;s compare the two sets of values.  I&#8217;ve found a great little charting tool for small sets of data over at <a href="http://code.google.com/apis/chart/"> Google</a>.  Here&#8217;s what it comes up with:<br clear="all" /><br />
<center><br />
<img src="http://chart.apis.google.com/chart?chtt=NFL+Streaks&amp;chts=000000,16&amp;chs=500x200&amp;chf=bg,s,ffffff|c,s,ffffff&amp;chxt=x,y&amp;chxl=0:|1|2|3|4|5|6|7|8|9|10|1:|0|10|20|30|40|50|60|70|80|90|100&amp;cht=lc&amp;chd=t:82.29,31.25,22.91,8.33,5.20,4.16,2.08,0.00,0.00,2.08|100.00,45.83,20.83,9.37,4.16,1.82,.78,.32,.13,.06&amp;chdl=Actual+Streaks|Expected&amp;chco=009933,cc6666&amp;chls=1,1,0|1,1,0" alt="Google Chart"/><br clear="all"/><br />
</center><br />
Hmmm, these don&#8217;t seem to be very different, do they?  As you can see, it seems this season isn&#8217;t very abnormal at all; with only moderate drops in the number of 1- and 2-game streaks to account for the obvious outlier of having 2 undefeated teams this late in the season.  Each streak length is very close to the expected count for that length.<br clear="all" /><br />
<img src="/art/sports/streaker.jpg" class="inline_pic right_pic" />There would seem to be several reasons one could come up with for why long streaks should occur in football: the literally outstanding talent on certain teams compared to others, the non-random nature of scheduling often pitting teams against obviously &#8220;unfair&#8221; set of opponents, even the difference between having to play certain teams at home or at the away park with largely varying weather.  Yet it seems that the schedule is &#8220;fair&#8221;, that the teams are well matched.  The math we&#8217;ve done here has shown that my anecdotal musings of unusually large streaks are without basis.  How cool is that?<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
<br clear="all" /></p>
]]></content:encoded>
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		</item>
		<item>
		<title>Discretely simple</title>
		<link>http://www.discreteideas.com/2009/10/discretely_simple/</link>
		<comments>http://www.discreteideas.com/2009/10/discretely_simple/#comments</comments>
		<pubDate>Sun, 25 Oct 2009 14:00:43 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Fun]]></category>
		<category><![CDATA[Learning]]></category>
		<category><![CDATA[Proofs]]></category>
		<category><![CDATA[math]]></category>
		<category><![CDATA[geometry]]></category>
		<category><![CDATA[proof]]></category>
		<category><![CDATA[sum]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=193</guid>
		<description><![CDATA[<p>I&#8217;ve said it before, and I&#8217;ll say it again &#8211; I like math.  Now, don&#8217;t get me wrong; I don&#8217;t run around solving Fermat&#8217;s Last Theorem for fun on Sunday nights, or anything like that.  Perhaps it would be more clear to say I enjoy math, for many reasons, not the least of which [...]]]></description>
			<content:encoded><![CDATA[<p><img src="/art/teach/sphere.jpg" class="inline_pic left_pic" />I&#8217;ve said it before, and I&#8217;ll say it again &#8211; I like math.  Now, don&#8217;t get me wrong; I don&#8217;t run around solving Fermat&#8217;s Last Theorem for fun on Sunday nights, or anything like that.  Perhaps it would be more clear to say I <i>enjoy</i> math, for many reasons, not the least of which is, when you prove something in math, it&#8217;s true <b><i>every time</i></b>!<br clear="all" /><br />
Since merely saying, &#8220;I can&#8217;t find a contradictory example&#8221; is never accepted as &#8220;it&#8217;s always true&#8221;, mathematical proofs are often filled with a multitude of complex concepts and references to <i>other</i> also very complex proofs.  It&#8217;s very refreshing, I think, to find a few that are so simple and elegant, they make you wonder if there aren&#8217;t very simple proofs for those other theorems, that we just haven&#8217;t discovered yet.  Here I present two of my favorite math proofs.  I hope you&#8217;ll enjoy them as much as I do.<br />
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It&#8217;s well known that the sum of the integers from 1 to N is N*(N+1)/2, and this can easily be verified for any number you care to choose.  However, it&#8217;s the <i>proof</i> for this statement that&#8217;s makes it so I can say that it&#8217;s true for ALL positive integers.  To find the sum for an unknown N, see the image below.<br clear="all" /><br />
<center><img src="/art/teach/sum1-N.jpg" /></center><br clear="all" /><br />
First, write the numbers from 1 to N across the top, then write the same numbers underneath those, only in reverse order.  This gives us N columns of numbers which we can now sum individually; as it happens, each column totals N+1.  The sum of all these N columns must be N*(N+1) and, since we used all the numbers 1 to N twice each in the rows, we need only divide that sum by 2 to find the solution to our problem&#8230;  N*(N+1)/2.  This elegant little exercise <i>proves</i> that the sum will always work out to that formula.  How cool is that?<br clear="all" /><br />
<img src="/art/teach/hemisphere1.jpg" class="inline_pic right_pic" />The second proof is a little more esoteric.  While it may not be entirely as useful in your life as the previous proof (if you found that one so), it&#8217;s another example of just how simple and elegant some math proofs can be (though most aren&#8217;t).  Look at the image on the right.  The blue shape is a semicircle where A-B is a diameter.  What&#8217;s not entirely intuitive and/or noticeable from the picture is that all 3 of the angles (marked 1, 2, and 3) are 90-degree or right angles.  In fact, the angle formed by the segments between any point on the semicircle and the 2 diametric points must be a right angle.  Useful information?  Maybe not, but let&#8217;s look at how we know it&#8217;s <i>always</i> true.<br clear="all" /><br />
<img src="/art/teach/hemisphere2.jpg" class="inline_pic left_pic" />In the picture on the left, we take a look at a single arbitrary example of the angle. By treating it in a completely generic fashion, what we do will be applicable to all possible angles.  Note that an additional segment has been drawn from the point D to the center of the diameter (and of the entire circle, were it shown) at point C.  The angle we&#8217;re trying to prove is a right angle is the sum of the two angles a and ß.  Now, since AC and CD are both radii of the semicircle, they must have the same length, and their corresponding angles in the smaller triangle ACD must be equivalent (we&#8217;ll call that a).  The same thing goes for the BCD triangle, only the angle there is probably different than the ACD pair, so we&#8217;ll call it ß.  Now, since ABD is a triangle too, its angles must total 180 degrees, yet from our previous statements, it must also total 2*a + 2*ß.  Basic algebra will reveal that (a+ß) <b>must</b> equal 90 degrees.  Simple and elegant, just as I promised.<br clear="all" /><br />
<img src="/art/teach/blackboard.jpg" class="inline_pic right_pic" />Well, these are just two of my favorite math proofs.  While neither is exactly mind-shattering, I hope they show that it is possible to prove something mathematically without obscure references to complex transformational theorems and multitudinous graphs and charts.  The next time you see a numeric pattern or shortcut, make a try at proving it.  You may just come up with a short method that&#8217;s eluded us all.<br clear="all" /><br />
<span class="count_sign">The Count</span><br />
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		<title>Litter By Numbers</title>
		<link>http://www.discreteideas.com/2009/10/litter-by-numbers/</link>
		<comments>http://www.discreteideas.com/2009/10/litter-by-numbers/#comments</comments>
		<pubDate>Fri, 09 Oct 2009 04:31:20 +0000</pubDate>
		<dc:creator>The Count</dc:creator>
				<category><![CDATA[Fun]]></category>
		<category><![CDATA[Learning]]></category>
		<category><![CDATA[geocache]]></category>
		<category><![CDATA[hobby]]></category>
		<category><![CDATA[world]]></category>

		<guid isPermaLink="false">http://www.discreteideas.com/?p=182</guid>
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<p>About two years ago, I got interested in Geocaching1.  I call it &#8220;organized littering&#8221;.   Essentially, people have taken the time to hide caches (usually tupperware containers full of bric-a-brac) all over the world.  They then log the lat/long coordinates of their stash, and enter them along with a [...]]]></description>
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<p><img src="/art/world/gps.jpg" class="inline_pic left_pic" />About two years ago, I got interested in Geocaching<span class="link_id">1</span>.  I call it &#8220;organized littering&#8221;.   Essentially, people have taken the time to hide caches (usually tupperware containers full of bric-a-brac) all over the world.  They then log the lat/long coordinates of their stash, and enter them along with a description on the GeoCaching site<span class="link_id">2</span>.  The rest of us use that site to find caches near where we&#8217;ll be, and off we go using our portable GPS units to find these little pockets of fun all over the world.<br clear="all" /><br />
<span id="more-182"></span>Our family was vacationing in the Pocono Mountains when we starting &#8216;caching.  I had researched several caches in the area, so one day my father, my wife, my son, and I all headed out into the wilderness.  We spent all day traipsing around and seriously enjoyed ourselves getting dirty.  The locations we found were a little remote and, since it was summer, the foliage was dense enough to block the view of much.  When I decided to write about it, I got to thinking how cool it would be to look for caches in exotic locations.  So here they are, some of the coolest locations in the Northern Hemisphere to go looking for litter.<br clear="all" /></p>
<table>
<thead style="font-weight: bold">
<td width="33%">Location</td>
<td width="27%">Lat</td>
<td width="27%">Long</td>
<td width="10%"></td>
</thead>
<tr>
<td width="30%">Pyramids of Egypt</td>
<td width="15%">N 29° 58&#8242; 34.00&#8243;</td>
<td width="15%">E 31° 07&#8242; 52.00&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=ce4793f2-d6b1-4b5b-8e8d-7b2991fa22f1">link</a></td>
</tr>
<tr>
<td width="30%">Stonehenge</td>
<td width="15%">N 51° 10&#8242; 43.00&#8243;</td>
<td width="15%">W 01° 49&#8242; 52.85&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=f6708379-911a-47ac-b329-3fec8d8858f8">link</a></td>
</tr>
<tr>
<td width="30%">Mall of America</td>
<td width="15%">N 44° 51&#8242; 13.64&#8243;</td>
<td width="15%">W 93° 14&#8242; 32.43&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=1bd1f64d-9103-49d2-a4fd-c8b0a93a6b9c">link</a></td>
</tr>
<tr>
<td width="30%">Waimea Canyon, Kaua&#8217;i</td>
<td width="15%">N 22° 02&#8242; 55.00&#8243;</td>
<td width="15%">W 159° 39&#8242; 29.49&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=3df2ccb9-d8d3-4f8f-898d-a7067bd9129f">link</a></td>
</tr>
<tr>
<td width="30%">Goat Island, Niagra Falls</td>
<td width="15%">N 43° 04&#8242; 50.15&#8243;</td>
<td width="15%">W 79° 04&#8242; 07.92&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=f1a57cd3-6573-4860-a108-f0f3de8381b9">link</a></td>
</tr>
<tr>
<td width="30%">Eiffel Tower</td>
<td width="15%">N 48° 51&#8242; 21.46&#8243;</td>
<td width="15%">E 02° 17&#8242; 27.75&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=890c51e5-d6d8-418a-8d5c-ca8ffc69ce67">link</a></td>
</tr>
<tr>
<td width="30%">Checkpoint Charlie, Berlin</td>
<td width="15%">N 52° 30&#8242; 23.33&#8243;</td>
<td width="15%">E 13° 23&#8242; 24.69&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=a6fa0b91-63e5-4be8-972c-5d379c0c6b40">link</a></td>
</tr>
<tr>
<td width="30%">Tarifa, Spain</td>
<td width="15%">N 36° 00&#8242; 35.10&#8243;</td>
<td width="15%">W 05° 36&#8242; 24.01&#8243;</td>
<td width="40%"><a href="http://www.geocaching.com/seek/cache_details.aspx?guid=8e09d4cd-6117-4cc8-9dfc-099d4f77e6d3">link</a></td>
</tr>
</table>
<p><img src="/art/world/globe.jpg" class="inline_pic right_pic" />Now, I know you&#8217;re just going to run out and fly to all these great places just to go find the closest cache, right?  Ok, maybe not, but I hope I peaked your interest in Geocaching, it&#8217;s a great way to learn about global coordinate systems and geography.  The next time you have a free Saturday afternoon or want a reason to take a hike, give it a try.<br clear="all" /><br />
<span class="count_sign">The Count</span></p>
<ol>
<li><a href="http://en.wikipedia.org/wiki/Geocaching">Geocaching on Wikipedia</a></li>
<li><a href="http://www.geocaching.com">GeoCaching site</a></li>
</ol>
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