This tells you that an integer is divisible by 4 if the number made from the two least significant digits is divisible by 4.

This is true because if N is the number M the number made from the two least significant digits, then:

N=100k + M

for some integer k. But 100 is divisible by 4, hence N is divisible by 4 if and only if M is divisible by 4.

RonL