Addition and Subtraction within 20

Front

4 + ? = 5

Back

1

Front

19 - ? = 15

Back

4

Front

1 + 1 = ?

Back

2

Front

13 + 13 = ?

Back

26

Front

20 + 20 = ?

Back

40

Front

5 + ? = 10

Back

5

Front

15 - ? = 10

Back

5

Front

3 + 2 = ?

Back

5

Front

10 - ? = 7

Back

3

Front

8 + ? = 12

Back

4