Student Success Series

Divisor tricks
Quick, easy tips to determine if a number is divisible by another number.
Divisible by 2, last digit has to be even number
           Example: 392 – last number is even so is divisible by 2
                                392/2=196
Divisible by 3, sum of digits has to be divisible by 3
           Example: 234 – 2+3+4=9, 9 is divisible by 3
                                234/3=78
Divisible by 4, last 2 digits has to be divisible by 4
           Example: 524 – last two digits is 24 which is divisible by 4
                               524/4=131
Divisible by 5, last digit is either a 0 or 5
           Example: 675 – ends in a 5 so is divisible by 5
                               675/5=135
Divisible by 6, Divisible by 2 and 3 (use rules for 2 and 3)
            Example: 336 – last digit is an even number so it is divisible by 2
                            Sum of digits, 3+3+6=12 which is divisible by 3
                                336/6=56
Divisible by 8, sum of last 2 digits and divisible by 4, usually works
            Example: 624/8 =78
                            However, if we use 524, the number used in our example above for being divisible by four, the rule for four works, but not for 8.
                             524/8=65.5
Divisible by 10, last digit has to be a 0.
            Example: 900/10=90