DS8's first "written math proof".
Question:  Genet multiplied a 3-digit number by 1002 and got AB007C, where A, B, and C stand for digits. What was Genet's original 3-digit number?
DS8's answer (I transcribed his exact words):  The answer is 539.  y=3 because in the 7C, 3+3 is 6, Z has to be a number 5 - 9 to make the 6 a 7.  x is 5 because the number under 2x is a 0, so it has to be 10 no matter what.  10 divided by 2 is 5 so x is 5.  The number under Z is zero, but since the 2x is added up to a 10, z has 1 more, so z has to be 9.  so xyz = 539.