zeertheseer wrote:
I am whats considered an extremely idiotic genius, at least that is what people know call me. things like, so you can explain human anatomy with extreme detail but can't figure out most multiplication tables?... its not that easy.....
I never memorized the whole multiplication table. Instead I figured out tricks for many of them.
5 * a = (a / 2) * 10
Divide the number in two, then times it by 10 instead of 5.
9 * a = ((a - 1) * 10) + (9 - (a - 1))
Take the number minus 1 and times it by 10. Then take the number in the tens and figure out how much you'd need to add to get to 9, and that's what's in the 1s. (9 times anything under 11 always has two digits that add up to 9. Above that, they always add to a multiple of 9.)
8 * a = ((2 * a) * 2) * 2
Take the number and times it by 2, then times it by two again, and then times it by 2 a third time.
I'm slightly slower at answering, but it was a lot more fun.