Mini-math: Flash Mind Reader
So here's one for all you algebra 1 buffs / students. Why does this "Flash Mind Reader" work? After being wowed a couple of times (or not), try to find a pattern in the numbers you end up with then an explaination and proof to solve it.
I put a solution in the comments, if you want to see if you are right (or you're just lazy).
1 comment:
Ok, so any 2-digit number and the sum of those digits can be represented by
10x + y
and
x + y
respectively, where x and y are single digit integers. If you subtract the second expression from the first, you get
9x ( like the yellow pages :) )
What this means is that no matter what 2-digit number you choose, the difference the "Flash Mind Reader" has you find is always going to be a multiple of 9.
If you look at the grid of numbers, the symbols next to all the multiples of 9 (9, 18, 27...) are always the same for each "reading". The rest of the symbols are garbage, as they can never be what you were "thinking" of.
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