Base 10 Blocks
21 + 45 = ___
66
34 + 52 = ___
86
12 + ___ = 30
45 - 25 = ___
20
45 - 15 = ___
30
56 - 13 = ___
43
32 - ___ = 19
13
55 + 23 = ___
78
37 + 45 = ___
82
34 + 57 = ___
91
51 + ____ = 82
31
47 + 21 = ___
68
51 - 18 = ___
33
42 - 38 = ___
76 - ___ = 45
31
68 - 35 = ___
33