Number Bonds to 100: Games, Tricks & Worksheet
Number bonds to 100 are pairs of numbers that add up to 100, like 35 + 65 and 80 + 20. Knowing them by heart makes adding, subtracting and making change much faster.
🔟 Play the number bonds to 100 game 🖨️ Printable worksheet
Tricks that make it easier
- Use bonds to 10 for the tens: 30 + 70 = 100.
- For numbers like 35, the ones make 10 (5 + 5) and the tens make 90: 35 + 65 = 100.
- Count up to the next ten, then to 100: 38 → 40 (2), then 60 more, so 62.
Try these
- 100 − 50 =
Answer
50 - 45 + ___ = 100
Answer
55 - 85 + ___ = 100
Answer
15 - 100 − 40 =
Answer
60 - 100 − 20 =
Answer
80 - 55 + ___ = 100
Answer
45
Common mistakes
- Making the tens add to 100 and forgetting the ones (35 + 75 = 110).
- Forgetting that the ones must make 10.
A five-day practice plan
| Day | What to do (10 minutes) |
|---|---|
| Day 1 | Play Number Bonds on this skill for 5–10 minutes. Read the explanation after every mistake. |
| Day 2 | Learn one trick from this page and use it out loud while you play. |
| Day 3 | Print the worksheet and try it without help. Mark it with the answer key together. |
| Day 4 | Play again and try to beat your personal best score or get three stars. |
| Day 5 | Mix it up: ask your child to explain the skill to you in their own words. |
Suits Grade 2 and Grade 3.
Frequently asked questions
What are number bonds to 100?
Pairs of whole numbers that add up to 100.
Why are number bonds important?
They are the foundation of mental math: bridging through 10, subtraction, money and change all depend on them.
How many number bonds to 100 are there?
Counting whole numbers, there are 101 pairs (0 + 100 up to 100 + 0), but children usually learn the multiples of 5 and 10 first.