what divides evenly into:
0
#
2
last digit is even
3
digits sum to a multiple of 3
4
last two digits are a multiple of 4
5
last digit is a 0 or 5
6
divisible by 2 and 3
8
last three digits are divisible by 8
9
digits sum to a multiple of 9
10
last digit is a 0
12
divisible by 3 and 4
15
divisible by 3 and 5