6th May 2022

Super Simple Divisibility Rules

You've got 210 pieces of pizza and want to know whether or not you can split them evenly within your group. Rather than whip out the calculator, use these simple shortcuts to do the math in your head:

• Divisible by 2 if the last digit is a multiple of 2 (210).
• Divisible by 3 if the sum of the digits is divisible by 3 (522 because the digits add up to 9, which is divisible by 3).
• Divisible by 4 if the last two digits are divisible by 4 (2540 because 40 is divisible by 4).
• Divisible by 5 if the last digit is 0 or 5 (9905).
• Divisible by 6 if it passes the rules for both 2 and 3 (408).
• Divisible by 9 if the sum of the digits is divisible by 9 (6390 since 6 + 3 + 9 + 0 = 18, which is divisible by 9).
• Divisible by 10 if the number ends in a 0 (8910).
• Divisible by 12 if the rules for divisibility by 3 and 4 apply.

Example: The 210 slices of pizza may be evenly distributed into groups of 2, 3, 5, 6, 10.