Number Bonds to 20 Games Online Free
Find the number that makes 20, like 13 + □ = 20. Each bond to 20 is a bond to 10 with an extra ten.
Type answers on your keyboard, or tap the number pad.
Practise these again:
What are number bonds to 20?
Number bonds to 20 are pairs of numbers that add up to 20, like 13 and 7 or 6 and 14. There are 21 of them, from 0 + 20 to 20 + 0.
They follow straight from the bonds to 10. Since 3 + 7 = 10, 13 + 7 = 20. If the bonds to 10 aren’t secure yet, start with make ten. The same idea later gives number bonds to 100.
How to play Number Bonds to 20
- Choose the 60-second challenge or untimed practice, then press Start.
- Type each answer on your keyboard or tap the number pad. It’s checked as soon as you’ve typed enough digits, or press ✓.
- Get one wrong and you’ll see the right answer, and the question comes back a little later.
- At the end, check your score and the facts to practise again.
Number Bonds to 20 skills
- Pairs of numbers that make 20
- Using bonds to 10 to find bonds to 20
- Finding a missing part
Level: Grades 1–2 (ages 6–8)
Tips for number bonds to 20
Look at the ones digit and use the bond to 10: for 16 + □ = 20, 6 + 4 = 10, so the answer is 4.
For a single-digit number, the answer is a teen number: 7 + 13 = 20.
Double check with doubles: 10 + 10 = 20 sits in the middle of every pair.
Number Bonds to 20 questions and answers
How do number bonds to 10 help with 20?
Every bond to 20 is a bond to 10 with one more ten. 4 + 6 = 10, so 14 + 6 = 20 and 4 + 16 = 20.
What year group learns number bonds to 20?
In England, number bonds to 20 are a Year 1 and Year 2 objective. In the US they’re part of first and second grade addition within 20.
Does the game show the missing number in both places?
Yes. Some questions ask 13 + □ = 20 and others ask □ + 7 = 20, so children get used to the blank in either spot.