Divisibility by which number is understood by checking the last two digits?

A number with 2 or more digits is divisible by 4 if the number formed by the last two digits (last from left) is divisible by 4. 

Example: Consider 552. 

Now,

Last two digits 52 is divisible by 4.

Therefore, 552 is divisible by 4. 

So, divisibility by 4 is understood by checking the last two digits.