70

80

70

80

70÷2

80÷2

35

40

35÷5

40÷5

7

8

or

70

80

2 × 5 × 7

2 × 2 × 2 × 2 × 5

7

8

or

Common Divisors for 70 and 80 are: 2 and 5

Greatest Common Divisor = 2 × 5 = 10

70÷10

80÷10

7

8

See 7/8 as a percent