Shortcuts for Divisibility by 2,3 and 4

Here are a set of time saving divisibility shortcuts that you can use:

Divisibility by 2:

How to check a number is divisible by 2?
It is very simple, first we should check the units digit of the number, whether it is divisible by 2. A number is divisible by 2, only when its unit digit contains 0, 2, 4, 6, 8.

Examples:
Is the number 6542646882 divisible by 2?
Now, check the units digit of the number, it is 2, so 6542646882 is divisible by 2.

Divisibility by 3:
How to check a number is divisible by 3?
It is very simple, first sum all the digits of the number, now check whether the result is divisible by 3. If the answer is divisible by 3, clearly the number will be divisible by 3.

Examples:
Is the number 6466545 divisible by 3?
Now, sum the digits of the number,
6 + 4 + 6 + 6 + 5 + 4 + 5 = 36
36 is divisible by 3, so 6466545 is divisible by 3.

Is the number 544733369 divisible by 3?
5 + 4 + 4 + 7 + 3 + 3 + 3 + 6 + 9 = 44
44 is not divisible by 3, so the number 544733369 is not divisible by 3.

Divisibility by 4:
How to check a number is divisible by 4?
It is very simple, first check the last two digits of the number is divisible by 4, then the number will be divisible by 4.

Examples:
Is the number 98731812 divisible by 4?
Take the last two digits in the given number,
Last two digit is 12, which is divisible by 4,
So 98731812 is divisible by 4.

Is the number 3426941365 divisible by 4?
The last two digit of the number is 65, which is not divisible by 4,
So the number 3426941365 is not divisible by 4.