4 number facts + -

Know 1 fact know 4

16 + 4 = 20

16

20

4

Each number sentence can be written in four ways.

Learn one, know four

+

=4 + 16 = 20

16

20

4

+

=20 – 4 = 16

16

20

4

=

–20 – 16 = 4

16

20

4

=

–

20 – 8 = 12

20 – 12 = 8

12 + 8 = 20

8 + 12 = 20 14 + 6 = 20

6 + 14 = 20

20 – 6 = 14

20 – 14 = 6

Learn one, know four

20 – 8 = 12

20 – 12 = 8

12 + 8 = 20

8 + 12 = 20 14 + 6 = 20

6 + 14 = 20

20 – 14 = 6

Can you fill in the gaps?

20 – 6 = 14

Learn one, know four

9 + 7 = 16

When you learn one number fact, you are really learning four.

If we learn…

9 + 5 = 14

Learn one, know four

What is the missing figurein these?

Then we also know…

5 + 9 = 1414 – 9 = 514 – 5 = 9

7 + 9 = 16

16 – 7 = 9

16 – 9 = 7

7 + 9 = 16

9 + 7 = 16

16 – 7 = 9

16 – 9 = 7

Learn one, know four