1.
Count backwards by 2s: 12, 10, 8, ___, 4, 2
2.
Count backwards by 2s: 14, 12, ___, 8, 6, 4
3.
Count backwards by 3s: 21, 18, ___, 12, 9, 6
4.
Count backwards by 2s: 10, ___, 6, 4, 2, 0
5.
Count backwards by 2s: 14, ___, 10, 8, 6, 4
6.
Count backwards by 3s: 18, 15, ___, 9, 6, 3
7.
Count backwards by 3s: 15, 12, 9, ___, 3, 0
8.
Count backwards by 3s: 24, 21, 18, ___, 12, 9
9.
Count backwards by 2s: 16, ___, 12, 10, 8, 6
10.
Count backwards by 3s: 15, 12, 9, 6, ___, 0
11.
Count backwards by 2s: 18, 16, 14, ___, 10, 8
12.
Count backwards by 2s: 18, 16, 14, ___, 10, 8
13.
Count backwards by 3s: 15, ___, 9, 6, 3, 0
14.
Count backwards by 2s: 14, ___, 10, 8, 6, 4
15.
Count backwards by 3s: 15, 12, ___, 6, 3, 0
16.
Count backwards by 2s: 10, 8, 6, ___, 2, 0
17.
Count backwards by 3s: 15, 12, ___, 6, 3, 0
18.
Count backwards by 2s: 16, 14, 12, ___, 8, 6
19.
Count backwards by 2s: 16, 14, 12, 10, ___, 6
20.
Count backwards by 2s: 16, 14, 12, ___, 8, 6