Addition Within 10
Addition within 10 is the base of every later sum. Children start by counting on from the bigger number and soon know the facts by heart: 6 + 3 = 9 without counting.
Three strategies
- Count on from the bigger number: 2 + 6 → start at 6 and count 7, 8. The answer is 8.
- Doubles: 4 + 4 = 8, 5 + 5 = 10. Near doubles follow: 4 + 5 is one more than 4 + 4, so 9.
- Number bonds to 10: 7 + 3, 6 + 4, 8 + 2. These pairs make missing-number tasks easy: 6 + __ = 10 → 4.
3 + 4
- Start at the bigger number, 4.
- Count on 3 more: 5, 6, 7.
Answer: 7
6 + __ = 10
- Which number makes 10 together with 6?
- The bond partner of 6 is 4.
Answer: 4
All number bonds to 10
- 0 + 10 = 10
- 1 + 9 = 10
- 2 + 8 = 10
- 3 + 7 = 10
- 4 + 6 = 10
- 5 + 5 = 10
Examples
3 + 4 = ?
7
6 + ? = 10
4
Practice problems with answers
Solve these problems on paper or out loud, then check the answer key. The online practice and the printable worksheet give a new set every time.
- 8 + ___ = 10
- 6 + ___ = 7
- 5 + ___ = 9
- 7 + ___ = 9
- 4 + 2 = ___
- 5 + 4 = ___
- 5 + 1 = ___
- 2 + 5 = ___
Show answers
- 2
- 1
- 4
- 2
- 6
- 9
- 6
- 7
Common mistakes
- Counting the starting number again: 4 + 3 → "4, 5, 6" gives 6 instead of 7.
- Always counting from 1, which is slow and leads to errors.
- Not seeing that 3 + 5 and 5 + 3 are the same fact.
Questions parents ask
How many addition facts within 10 are there?
There are 66 facts with both numbers from 0 to 10 and a sum up to 10. There are far fewer to learn once the child knows that 3 + 5 = 5 + 3.
Should my child use fingers?
Fingers are fine at the start. The goal is to move on to counting on and then to knowing the facts, so the fingers are needed less and less.