Question

What is the digit at the unit's place of
1!+2!+3!+........99!

Answer 1

5

Answer 2

apparently it is 3, but i have no idea why

Answer 3

It's 3 because 5! is 120 and anything greater than that has a unit digit of 0 so all you have to do is 1! + 2! + 3! + 4! which is 33 so the answer is 3.

Answer 4

oh maybe i do, because after 5! you will get nothing in the 1's place

Answer 5

right! what supermarth said

Answer 6

Oh wow!! how clever