Pairs that make 10 are very useful: 1 and 9, 2 and 8, 3 and 7, 4 and 6, and 5 and 5. A ten frame has 10 spaces, so you can see how many more fill it up.
When you know these pairs, bigger sums get easier. For 8 + 5, take 2 from the 5 to make 10, then add the 3 that is left: 10 + 3 = 13.
Worked example
7 + ☐ = 10. What is the missing number?
- Start at 7 and count up to 10: 8, 9, 10.
- That is 3 more.
Answer:3
Key words
- number bond
- two numbers that make a total
- ten frame
- a box with 10 spaces
- make ten
- find the number that fills it to 10
Practise this
New questions every time.
Common Core-referenced: 1.OA.C.6