Remember how we can use
partitioning to help us to subtract?
43 – 12 =
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
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!
43 – 15 =
We need to cross
out 5 units and we
only have 3 but
how many units are
in one ten?
43 – 15 =
Lets break up one ten
to make ten units.
43 – 15 =
Now can we cross out
1 ten and 5 units?
43 – 15 =
25
21
10
20
24
26
22
27
23
28
Now count what is left.
43 – 15 =
25
21
10
20
24
26
22
27
23
28
43 – 15 = 28
Try some on your own.
34 – 17 =