Understand the idea.
Split to help yourself
Partition means split a number into parts with the same total. Choose parts that help you reach a ten: for , split six into three and three, because . Other splits are possible, but this one gives easy jumps.
Keep all the parts
Use every part once. Splitting into means needs a subtraction of ten and then eight. Label the jumps so you can check that their sizes add to the full amount being subtracted.
See the method in action.
Cross a ten when adding
Find 56 + 8.
Worked solution
- 1
Choose a split that reaches sixty.
Fifty-six needs four more to reach the next ten.
- 2
Add the first four.
The first jump lands exactly on sixty.
- 3
Add the other four.
The second jump completes the full addition of eight.
64
Cross a ten when subtracting
Find 42 − 7.
Worked solution
- 1
Choose a split that reaches forty.
Removing two from forty-two reaches a ten, with five still to remove.
- 2
Subtract the first part.
The first jump takes away two of the seven.
- 3
Subtract the remaining part.
The two jumps remove seven altogether, so the result is thirty-five.
35
Try it yourself.
Check your understanding
Use 10 + 6 to find 35 + 16.
Show answer & reasoning
51
The parts total sixteen. Add them in order: , then .
Keep practising
6 worksheet questions
Read the questions online
- Split 38 into tens and ones.
- Find by making 30 first.
- Find by reaching 70 first.
- Find using .
- Find using .
- Mina splits 9 into to find . Finish her method.
Read the worked solutions
- Split 38 into tens and ones.
3 tens are 30 and there are 8 ones.
- Find by making 30 first.
Split 7 as : .
35 - Find by reaching 70 first.
Split 6 as : .
65 - Find using .
; .
67 - Find using .
; .
68 - Mina splits 9 into to find . Finish her method.
; .
45
Curriculum reference & lesson scope
Australian Curriculum v9 and SA Curriculum Mathematics
Facts within 20; one-/two-digit calculations; partitioning; related facts; missing numbers; checking.
Official curriculum source ↗