To check weather the number is divisible by 3 and 4 then when should know the divisibility rule of 3 and 4.
A number is said to be divisible by 3 when the sum of each digit of the number is divisible by 3. Example 9+8+4 = 21 is divisible by 3 hence the number is divisible by 3.
A number is said to be divisible by 4 when the last two digit is divisible by 4 like 84 is divisible by 4 hence 984 is divisible by 4.
