How to find number bonds to 100 quickly

For ages 7 to 10 (Years 3 to 5) · 2-minute read · free worksheet

Number bonds to 100 are pairs like 70 and 30 or 64 and 36. They build straight on number bonds to 10, so there is nothing new to memorise.

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Worksheet includes an answer key for grown-ups

How it works

  1. Look at the tens digit.
  2. Find its partner to 10.
  3. That many tens is the answer.

Worked example

80 + ? = 100. The 8 needs a 2 to make 10, so the answer is 20 (80 + 20 = 100).

Top tip

For numbers like 64: the ones make 10 (4 + 6) and the tens make 9 (6 + 3). So 64 + 36 = 100.
How to find number bonds to 100 quickly: 80 + ? = 100 8 and 2 make 10, so 20

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