70/5 = 12. Remainder 0

12/5 = 2. Remainder 2

2/5 = 0. Remainder 2

Write the remainder back from bottom to top to get 220.

7 inches

70/7 = 10. Remainder 0

7/7 = 1. Remainder 0

1/7 = 0. Remainder 1

Write back the remainder from bottom to top to get 100.

Divide this number by the number you want until it equals 0.