Being able to tell if a number can be divided by another number (aka divisibility) is a very helpful math skill used in many different types of problems, including long division and simplification of fractions. Here are some tricks that can help you determine the divisibility of a number!

1. Divisibility Rules
and Tricks

2. Dividing by 2
- All even numbers are divisible by 2! Even
numbers are numbers that end in 0, 2, 4, 6,
or 8.
- For example, 136 ends in 6, which is an
even number so 136 is divisible by 2.

3. Dividing by 3
- To see if a number is divisible by 3, try this trick.
- First, add up all the digits in a number.
- Then, see if the sum of your addition is divisible
by 3. If it is, then your number is also divisible by
3.
- For example, let’s do this with 78. 7+8=15 and
15 is divisible by 3 (15÷3=5), so 78 is also
divisible by 3!

4. Dividing by 4
- This trick shows whether a number is divisible by 4 or not,
but it only really works with numbers that have three or
more digits.
- If the last two digits in a number are divisible by four,
then the whole number is divisible by four.
- For example, let’s look at 316, which ends in 16. Since
16 is divisible by 4 (16÷4=4), 316 is divisible by 4.

5. Dividing by 5
- If a number ends in 0 or 5, then it is
divisible by 5!
- For example, 105 ends in a 5, so it is
divisible by 5.

6. Dividing by 6
- If a number is divisible by both 2 and 3, then it is divisible
by 6! Apply both the two and three divisibility tricks, and if
they both work, then the number is also divisible by 6.
- For example, let’s see if 96 is divisible by 6. It ends in an
even number, so it is divisible by 2. Now let’s use the
three divisibility trick. Adding together 9 and 6, we get 15,
which is divisible by 3, so 96 is also divisible by 3.
Therefore 96 is divisible by 6.

7. Dividing by 9
- The trick to see if a number is divisible by 9 is
similar to the three divisibility trick!
- Add up all the digits in a number. If the sum of the
digits is divisible by 9, then the number is too.
- For example, let’s try this with 189. 1+8+9=18
and 18 is divisible by 9 (18÷9=2), so 189 is
divisible by 9.

8. Dividing by 10
- If a number ends in 0, then it is divisible
by 10!
- For example, 140 ends in a 0, so it is
divisible by 10.