15

30

15

30

15÷3

30÷3

5

10

5÷5

10÷5

1

2

or

15

30

3 × 5

2 × 3 × 5

2 × ~~3~~ × ~~5~~

1

2

or

Common Divisors for 15 and 30 are: 3 and 5

Greatest Common Divisor = 3 × 5 = 15

15÷15

30÷15

1

2

See 1/2 as a percent