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Tuesday, December 7, 2010

Nerd Fest 2010

I LOVE MATH! It's seriously my FAVORITE!

Today while I was teaching math to Nicole I came across a chart filled with tricks for figuring out single digit factors of divisibility.  I knew the tricks for 2, 5, 9 and 10 (which is not a single digit...I know.) BUT, I did not know there are tricks for 3,4,6 and 8. SO, I'm going to share the awesomeness with you! You are welcome.

TESTS FOR DIVISIBILITY
a number can be divided by...
2   if the last digit can be divided by 2.
4   if the last two digits can be divided by 4.
8   if the last three digits can be divided by 8.
5   if the last digit is 0 or 5.
10 if the last digit is 0.
3   if the sum of the digits can be divided by 3.
6   if the number can be divided by 2 and 3.
9   if the sum of the digits can be divided by 9 (or if the equal nine with adding all numbers until a single digit. 2439 2+4+3+9=18 1+8=9.)

There is no simple test for divisibility by 7.  LAME!

But how awesome is that?

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