Question

Ayesha has a theory about 2 digit numbers that have a larger tens digit than ones digit she says that reversing the digits and subtracting the reversed number from the original number will always generate a number that is a multiple of 9 is ayesha right? If so why do you think this works? If not,why not?

Answer 1

$10x+y-(10y+x)=10x+y-10y-x=9x-9y=9(x-y)$

She's right.