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Divide fractions

Method: Keep, change, flip

Dividing asks how many of one thing fit into another. How many quarters fit in 3? Each whole has 4 quarters, so 3 ÷ 1/4 = 12. Dividing a fraction by a whole number shares it: 3/4 ÷ 2 = 3/8. For any division by a fraction, keep the first number, change ÷ to ×, and flip the second: 2/3 ÷ 3/4 = 2/3 × 4/3 = 8/9.

Explore this idea with maths tools

Equal parts, equal wholes

2/4 = 4/8

Both bars are the same length. Find a division of the second bar that lines up exactly with the coloured edge.

Words to know

reciprocal
a fraction flipped over, like 4/3 for 3/4
divisor
the number you divide by
keep, change, flip
keep the first number, change ÷ to ×, flip the divisor

Worked examples

3 ÷ 1/4 = ?

  1. 1.Each whole has 4 quarters.
  2. 2.3 wholes have 3 × 4 = 12 quarters.

= 12

3/4 ÷ 2 = ?

  1. 1.Dividing by 2 is multiplying by 1/2.
  2. 2.3/4 × 1/2 = 3/8.

= 3/8

2/3 ÷ 3/4 = ?

  1. 1.Keep 2/3, change to ×, flip 3/4 to 4/3.
  2. 2.2/3 × 4/3 = 8/9.

= 8/9

For parents

Method: Keep, change, flip

What to say: How many of these fit into that? Which number gets flipped?

Common mistakes:

  • Multiplies by the second number instead of dividing (3 ÷ 1/4 → 3/4).
  • Gives the number of unit pieces in one whole, ignoring how many wholes there are.
  • Flips the first number (the dividend) instead of the divisor before multiplying.
  • Multiplies the numerator and denominator by the whole number, making an equivalent fraction instead of dividing.
  • Flips both fractions before multiplying.