Understand the idea.
Use a friendly ten
Use a nearby ten to make adding easier. For , the needs to reach . Split into , make the ten, then add the remaining . Both parts of the are used.
Use what you know
A known fact can unlock another fact. Since , adding gives one more: . Addition also checks subtraction: if , then removing from leaves .
See the method in action.
Make ten
Find 9 + 6.
Worked solution
- 1
Split six to complete a ten.
Nine needs one more to reach ten, leaving five still to add.
- 2
Make the ten.
Using the first part of six reaches a friendly total.
- 3
Add the remaining part.
The one and five together account for all six added ones.
15
Use an addition fact
Find 14 − 6.
Worked solution
- 1
Turn subtraction into a missing-part question.
Removing six from fourteen leaves the amount needed to join six and make fourteen.
- 2
Count on through ten.
Four more reaches ten, and another four reaches fourteen.
- 3
Join the two jumps.
The missing part is eight, so .
8
Try it yourself.
Check your understanding
Find 7 + 6 using a double.
Show answer & reasoning
13
Double seven is . In , the second part is one less, so the total is also one less: .
Keep practising
6 worksheet questions
Read the questions online
- Find .
- Find .
- Find .
- Find .
- Find .
- Explain a way to find without counting by ones.
Read the worked solutions
- Find .
.
12 - Find .
Double 6 is 12.
12 - Find .
.
17 - Find .
.
9 - Find .
.
8 - Explain a way to find without counting by ones.
Split 7 into 2 and 5, then make ten.
For example, .
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 ↗