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Class 4

Chapter 6: Measuring Length

We measure length using a ruler or a tape. The most common units are centimetres (cm) and metres (m). 100 cm = 1 m.

Learning outcomes

  • Estimate and measure lengths in cm and m
  • Convert between units of length

Activities

  • Estimate-then-measure relay

Worked examples

Read through these first, then try the practice below.

  1. Example 1 — Convert 250 cm to metres

    How many metres is 250 cm?

    Solution: 100 cm = 1 m. 250 ÷ 100 = 2 m 50 cm, or 2.5 m.

  2. Example 2 — Estimate the length

    Which is the best estimate for the length of a school bench: 5 cm, 1 m or 50 m?

    Solution: 1 m is closest. 5 cm is too short; 50 m is far too long.

Self-do practice

Question 1 of 3 · Score 0/0

How many centimetres are there in 1 metre?

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