Use the addition fact

10 + 7 = 17

Now, subtract:

17 − 10 =

Use the addition fact

1 + 9 = 10

Now, subtract:

10 − 1 =

Use the addition fact

11 + 9 = 20

Now, subtract:

20 − 11 =

Use the addition fact

7 + 13 = 20

Now, subtract:

20 − 7 =

Use the addition fact

12 + 8 = 20

Now, subtract:

20 − 12 =

Use the addition fact

4 + 6 = 10

Now, subtract:

10 − 4 =

Use the addition fact

10 + 10 = 20

Now, subtract:

20 − 10 =

Use the addition fact

8 + 2 = 10

Now, subtract:

10 − 8 =

Use the addition fact

10 + 9 = 19

Now, subtract:

19 − 10 =

Use the addition fact

2 + 8 = 10

Now, subtract:

10 − 2 =

Use the addition fact

3 + 7 = 10

Now, subtract:

10 − 3 =

Use the addition fact

8 + 12 = 20

Now, subtract:

20 − 8 =

Use the addition fact:

6 + 4 = 10

Now, subtract:

10 − 6 =

Use the addition fact

14 + 6 = 20

Now, subtract:

20 − 14 =

Use the addition fact

9 + 11 = 20

Now, subtract:

20 − 9 =