Developing immediate recall of all addition families to 10 + 9. Also practicing a rapid mental process to add a 1 digit number ( 1 to ) to a 2 digit number making a sum less than 20.
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1 + 9 = ___
9 + 1 = ___
1 + ___ = 10
___ + 9 = 10
2 + 9= ___
9 + 2 = ___
2 + ___ = 11
___ + 9 = 11
3 + 9 = ___
9 + 3 = ___
3 + ___ = 12
___ + 9 = 12
4 + 9 = ___
9 + 4 = ___
___ + 4 = 13
9 + ___ = 13
5 + 9 = ___
9 + 5 = ___
5 + ___ = 14
___ + 9 = 14
6 + 9 = ___
9 + 6 = ___
6 + ___ = 15
___ + 9 = 15
7 + 9 = ___
9 + 7 = ___
7 + ___ = 16
___ + 9 = 16
8 + 9 = ___
9 + 8 = ___
8 + ___ = 17
___ + 9 = 17
9 + 9 = ___
___ + 9 = 18
9 + ___ = 18
10 + 9= ___
10 + ___ = 19
11 + 9 = ___
11 + ___ = 20
