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.