1.
Count backwards by 7s: 56, 49, 42, ___, 28, 21
2.
Count backwards by 6s: 42, ___, 30, 24, 18, 12
3.
Count backwards by 9s: 45, 36, ___, 18, 9, 0
4.
Count backwards by 2s: 18, 16, 14, 12, ___, 8
5.
Count backwards by 9s: 81, 72, 63, ___, 45, 36
6.
Count backwards by 2s: 12, 10, 8, 6, ___, 2
7.
Count backwards by 8s: 56, 48, 40, 32, ___, 16
8.
Count backwards by 3s: 24, 21, ___, 15, 12, 9
9.
Count backwards by 8s: 48, 40, 32, 24, ___, 8
10.
Count backwards by 5s: 45, 40, 35, ___, 25, 20
11.
Count backwards by 7s: 35, ___, 21, 14, 7, 0
12.
Count backwards by 5s: 25, 20, 15, 10, ___, 0
13.
Count backwards by 2s: 12, 10, ___, 6, 4, 2
14.
Count backwards by 5s: 30, 25, ___, 15, 10, 5
15.
Count backwards by 9s: 45, ___, 27, 18, 9, 0
16.
Count backwards by 5s: 35, 30, 25, ___, 15, 10
17.
Count backwards by 4s: 28, ___, 20, 16, 12, 8
18.
Count backwards by 3s: 27, 24, 21, 18, ___, 12
19.
Count backwards by 5s: 40, 35, 30, ___, 20, 15
20.
Count backwards by 3s: 18, ___, 12, 9, 6, 3