1. Remember how we can use partitioning to help us to subtract?
43 – 12 =

2. First draw the biggest number.
43 – 12 =
First draw the biggest number.
Now cross out the second number to subtract. 31
Count what is left. 10 20 30
43 – 12 = 31

3. We need to cross out 5 units and we only have 3!
43 – 15 =
First draw the biggest number.
Can we cross out the second number to subtract?
We need to cross out 5 units and we only have 3!

4. 43 – 15 =
We need to cross out 5 units and we only have 3 but how many units are in one ten?

5. Lets break up one ten to make ten units.
43 – 15 =
Lets break up one ten to make ten units.

6. Now can we cross out 1 ten and 5 units?
43 – 15 =
Now can we cross out 1 ten and 5 units?

7. 43 – 15 = 25 21 24 26 22 27 23 28 10 20
Now count what is left.

8. 43 – 15 = 25 21 24 26 22 27 23 28 10 20
43 – 15 = 28

9. Try some on your own.
34 – 17 =