
An integer is divisible by 2 if and only if,
The units digit is divisible by 2

An integer is divisible by 5 if and only if,
The units digit is a 0 or 5.

An integer is divisible by 10 if and only if,
The units digit is a 0.

An integer is divisible by 4 if and only if
the last two digits of the integer represent a number divisible by 4.

An integer is divisible by 8 if and only if,
the last three digits of the integer represent a number divisible by 8.

An integer is divisible by 3 if and only if,
the sum of it's digits is divisible by 3.

An integer is divisible by 9 if and only if,
the sum of its digits is divisible by 9

An integer is divisible by 11 if and only if,
the sum of the digits in the places that are even powers of 10 minus the sum of the digits in the places that are odd powers of 10 is divisible by 11.

An integer is divisible by 6 if and only if,
the integer is divisible by both 2 and 3

