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Missing Number Problems

Maths: Year 3 & 4 National Curriculum, topic 1.3.4

Missing Number Problems

We can use our knowledge of number relationships, number facts and inverse operations to find the missing number in a calculation.

Missing number

Missing number

  • Sometimes we have to work out the missing number in a multiplication or division equation.
  • This is not always the number after the = sign.
  • For example:
  • ? x 5 = 15
  • 4 ÷ ? = 2
Number facts

Number facts

  • We can use our knowledge to help find the missing number.
  • ? x 5 = 15
  • We know from our 5 times table that:
  • 3 x 5 is 15
  • The missing number is 3.
Bar models

Bar models

  • We can use bar models to find the missing number.
  • 24 ÷ ? = 4
  • We can see there are 6 squares. Each square is equal to 4.
  • The missing number is 6.
Inverse operations

Inverse operations

  • We can use inverse operations to find the missing number.
  • ? x 5 = 15
  • The inverse is 15 ÷ 5 = 3.
  • The missing number is 3.

Test yourself on Missing Number Problems

  • Using the bar model shown, what is the missing number?
    48 ÷ ? = 8

  • Using the bar model shown, what is the missing number?
    42 ÷ 6 = ?

  • Using the bar model shown, what is the missing number?
    8 × ? = 32

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