#33
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Re: Cool math shortcuts
I do this kinda crap when I'm bored. The one Homer came up with is something I figured out when I was 13 or so. There's a bunch that I read in some book, like squaring numbers where the first two digits are the same and the second two digits add up to ten.
39 * 31 (3*(3+1))(9*1) (12)(09) 1209 |
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