Divisibility rules
Divisibility rules of whole numbers are very useful because they help us to quickly determine if a number can be divided by 2, 3, 4, 5, 9, and 10 without doing long division. This is especially useful when the numbers are large.
Divisibility Rule of 1
Any integer that is not a fraction is divisible by 1.
Eg:- 23, 84, 974, 1023
Divisibility Rule of 2
If a number is an even number or a number whose last digit is an even number.
Eg:- 0, 2, 4, 6, 8, 10
Divisibility Rule of 3
When the sum of all digits of a number is a multiple of 3.
Eg:- 516, 36, 119, 5502
Divisibility Rule of 4
When the number formed by last 2 digits is divisible by 4.
Eg:- 92, 780, 52, 300
Divisibility Rule of 5
When the ones digit of the number is either 0 or 5.
Eg:- 55, 125, 1000, 760
Divisibility Rule of 6
A number is divisible by 6 if it is divisible by 2 and 3 also.
Eg:- 270, 630, 144, 42
Divisibility Rule of 7
When the difference between twice the digits at ones place and the number formed by other digit is either zero or a multiple of 7.
Eg:- 1073, 98, 56, 140
Divisibility Rule of 8
The number formed by last 3 digits is divisible by 8.
Eg:- 1792, 1824, 2000, 2880
Divisibility Rule of 9
When the sum of all digits of a number is a multiple of 9.
Eg:- 51984, 2979, 9000, 135
Divisibility Rule of 10
When the ones digit is zero.
Eg:- 1000, 150, 670, 280