Divisibility by 4
The number 100 is divisible by 4. Hence, a number ending with two zeros is divisible by 4.
For example, 500, 700, 300 are divisible by 4 because they end with two zeros. The numbers 6000 and 23 000 are also divisible by 4.
Let us take a number that does not end with zeros, for example, 916.
This number can be represented like the sum 900 + 16.
Because both the addends are divisible by 4, their sum 916 is also divisible by 4.
On the contrary, 918 is not divisible by 4 because 918 = 900 + 18 and one of the addends (18) is not divisible by 4.
From the examples we can see that we need only the second addend to determine divisibility by 4. The second addend consists of the last two digits.
So, the number 13724 is divisible by 4 because its last two digits, 24, are divisible by 4.
The number 13722 is not divisible by 4 because its last two digits, 22, are not divisible by 4.
For example, 450, 2506, 15342, 20018 are not divisible by 4.
540, 1256, 32424, 56300 are divisible by 4