Question 1
8 and 2 make __.
Year 1
Represent and use number bonds and related subtraction facts within 20
See a whole number as two parts and use that bond to write matching subtraction facts.
Lesson overview
Number - addition and subtraction
A number bond shows a whole and the two parts that make it. If the whole is 10 and one part is 6, the other part is 4. The same bond also helps us with subtraction facts because 10 take away 6 leaves 4, and 10 take away 4 leaves 6.
Each whole can be split into two parts. The same bond also gives two subtraction facts.
Worked example
Use the bond to complete the facts for 9.
- The whole number is 9.
- One part is 4 and the other part is 5.
- So the addition fact is 4 + 5 = 9.
- The matching subtraction facts are 9 - 4 = 5 and 9 - 5 = 4.
Round 1: Learn it
Look at the whole and the parts, then complete the matching fact.
Finish this round to unlock Round 2: Show you know it.
Question 2
14 is made of 10 and __.
Question 3
Complete the bond: 6 + __ = 10.
Question 4
Use the subtraction fact: 15 - 5 = __.
Question 5
Which subtraction fact matches the bond 7 and 6 make 13?
Common mistakes
These reminders help when using parts, wholes and subtraction facts.
- Using a part as the whole number by mistake.
- Forgetting that the two parts must add to the whole.
- Writing a subtraction fact that does not start with the whole.
Related topics
These connect closely to the bond facts in this lesson.
- Read, write and interpret mathematical statements using +, - and = signs.
- Add and subtract one-digit and two-digit numbers to 20, including zero.