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Year 5 · Multiplication and division · 15 min

Inverse fact families

Connect multiplication with its matching division facts and use the connection to check results.

01 / LEARN

The idea, step by step

Four facts describe one grouping

From 6 × 8 = 48, we also know 8 × 6 = 48, 48 ÷ 6 = 8 and 48 ÷ 8 = 6. These four facts form a fact family. Multiplication combines equal groups; division asks how many groups or how many in each group.

For a square fact such as 7 × 7 = 49, swapping the two factors gives the same multiplication sentence. There are only two different sentences: 7 × 7 = 49 and 49 ÷ 7 = 7. Do not invent extra numbers just to make four different facts.

The 6, 8 and 48 fact family
MultiplicationMatching division
6 × 8 = 4848 ÷ 6 = 8
8 × 6 = 4848 ÷ 8 = 6

Undo and check

If a number was multiplied by nine, dividing the result by nine recovers it. If 27 × 9 = 243, then 243 ÷ 9 = 27. This is useful for checking both operations.

Zero needs care. We know 0 × 5 = 0 and 0 ÷ 5 = 0, but we cannot divide by zero. A division sentence with zero as the divisor is not a valid extra fact. For ordinary four-sentence fact families, use non-zero factors.

A common trap

Reversing a division sentence as if division could always be swapped.

Instead: 48 ÷ 6 = 8 does not mean 6 ÷ 48 = 8. Multiplication factors may swap; a division dividend and divisor have different jobs.

02 / WORKED EXAMPLES

See the thinking

Example 1

Write a full family

Write the multiplication and division fact family for 9, 12 and 108.

  1. Use both orders of the two factors.
  2. Make the product the starting number for division.
  3. Use each non-zero factor as a divisor once.
9 × 12 = 108; 12 × 9 = 108; 108 ÷ 9 = 12; 108 ÷ 12 = 9.
Example 2

Check a large division

A learner writes 516 ÷ 6 = 86. Check using an inverse operation.

  1. Multiply the proposed quotient by six.
  2. 86 × 6 = 480 + 36 = 516.
  3. The check matches the original dividend.
The division is correct.

Check your understanding

Use 13 × 4 = 52 to write two related division facts.

Show answer

52 ÷ 13 = 4 and 52 ÷ 4 = 13.

Start each division with the product, fifty-two.

03 / WORKSHEET

Your turn

6 questions · 11 marks · Work at your own pace.

Read the questions online
  1. Write the two division facts linked to 7 × 9 = 63.
    1 mark
  2. Write a full fact family using 5, 18 and 90.
    2 marks
  3. Use multiplication to check 448 ÷ 8 = 56.
    2 marks
  4. A machine multiplies a number by six and produces 234. What inverse operation recovers the starting number?
    2 marks
  5. How many different multiplication/division sentences are in the fact family for 8, 8 and 64? Write them.
    2 marks
  6. Explain why 0 × 7 = 0 does not allow the division sentence 0 ÷ 0 = 7.
    2 marks
Read the worked solutions

Equivalent correct methods earn the corresponding marks. Include units where asked.

  1. Write the two division facts linked to 7 × 9 = 63.
    1 mark

    Start with sixty-three and divide by each factor.

    63 ÷ 7 = 9 and 63 ÷ 9 = 7.
  2. Write a full fact family using 5, 18 and 90.
    2 marks

    The factors multiply to ninety.

    5 × 18 = 90; 18 × 5 = 90; 90 ÷ 5 = 18; 90 ÷ 18 = 5.
  3. Use multiplication to check 448 ÷ 8 = 56.
    2 marks

    50 × 8 = 400 and 6 × 8 = 48.

    56 × 8 = 448, so it is correct.
  4. A machine multiplies a number by six and produces 234. What inverse operation recovers the starting number?
    2 marks

    Divide by the same non-zero factor.

    234 ÷ 6 = 39.
  5. How many different multiplication/division sentences are in the fact family for 8, 8 and 64? Write them.
    2 marks

    Swapping the equal factors repeats the same sentence.

    Two: 8 × 8 = 64 and 64 ÷ 8 = 8.
  6. Explain why 0 × 7 = 0 does not allow the division sentence 0 ÷ 0 = 7.
    2 marks

    Any number multiplied by zero gives zero, so this cannot identify one unique quotient.

    Division by zero is undefined.
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Curriculum reference & lesson scope

Australian Curriculum v9.0; SA Curriculum Mathematics 2026

One-/two-digit multipliers; division strategies; contextual remainders; inverse fact families; unknown factors/dividends/divisors.

Official curriculum source ↗
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