Divisibility Rules
By using divisibility rules we can easily find out whether a given number is divisible by another number without actually performing the division. This helps to save time especially when working with numbers.
Divisibility by 2
A number is divisible by 2 if the last digit is even. i.e., if the last digit is 0 or 2 or 4 or 6 or 8
Example1: Check if 64 is divisible by 2.
The last digit of 64 is 4 (even). Hence 64 is divisible by 2
Example2: Check if 69 is divisible by 2.
The last digit of 69 is 9 (not even). Hence 69 is not divisible by 2
Divisibility by 3
A number is divisible by 3 if the sum of the digits is divisible by 3
(Please note that we can apply this rule to the answer again and again if we need)
Example1: Check if 387 is divisible by 3.
3 + 8 + 7 = 18.
18 is divisible by 3. Hence 387 is divisible by 3
Example2: Check if 421 is divisible by 3.
4 + 2 + 1 = 7.
7 is not divisible by 3. Hence 421 is not divisible by 3
Divisibility by 4
A number is divisible by 4 if the number formed by the last two digits is divisible by 4.
Example1: Check if 416 is divisible by 4.
Number formed by the last two digits = 16.
16 is divisible by 4. Hence 416 is divisible by 4
Example2: Check if 481 is divisible by 4.
Number formed by the last two digits = 81.
81 is not divisible by 4. Hence 481 is not divisible by 4
Divisibility by 5
A number is divisible by 5 if the last digit is either 0 or 5.
Example1: Check if 305 is divisible by 5.
Last digit is 5. Hence 305 is divisible by 5.
Example2: Check if 420 is divisible by 5.
Last digit is 0. Hence 420 is divisible by 5.
Example3: Check if 312 is divisible by 5.
Last digit is 2. Hence 312 is not divisible by 5.
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