Multiples of 3 are numbers in the 3 times table. This means that if they were divided by 3, you would get a whole number. 

Whilst anyone who knows their 3 times tables will immediately know that 9 or 21 or 36 are multiples of 3, it isn’t obvious for larger numbers. Luckily, you can test if any number is a multiple of three by simply adding its digits together

If they add to another multiple of 3 (3, 6, 9, 12 etc.) then the number is a multiple of three

Example 1 => Is 5124 a multiple of 3?
Add the digits => 5 + 1 + 2 + 4 = 12.
Since 12 is in the 3 times table, then 5124 is a multiple of 3.

Example 2 => Is 1,234,567 a multiple of 3?
Add the digits => 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28.
Since 28 is not in the 3 times table, then 1,234,567 is not a multiple of 3.

Now try a few practice questions!