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Maths

Doubling and Halving

Overview

Using practical objects and body movements, students explore what doubling and halving mean and practise both operations fluently.

Learning Objective
Students understand doubling as adding a number to itself and halving as splitting equally into two, and apply both to numbers up to 20.

Resources needed

  • Counters or cubes
  • Mini whiteboards
  • Doubling and halving number cards (optional)

Lesson stages

0 / 7 done
  1. 1 Stand up. 'Double your arms!' (wave both arms). 'Double your claps!' Students clap twice as many as you do. Discuss: what does double mean?
  2. 2 Show 5 counters. 'I want to double this — I need the same again.' Add 5 more. '5 doubled is 10.' Now show 10 counters. 'If I halve this, I split it into two equal groups.' Count into two piles of 5. '10 halved is 5.'
  3. 3 Give pairs 20 counters. Call a number (e.g. 6). Partner A doubles it using counters; partner B finds the answer. Swap for halving. Pairs record: double 6 = 12, half of 12 = 6.
  4. 4 Write on board: double 1 = 2, double 2 = 4, double 3 = 6... 'What do you notice?' Students identify that doubling gives even numbers. 'Can you double an odd number? What happens?'
  5. 5 If double 8 = 16, what is half of 16? How do you know without using counters? Introduce the inverse relationship.
  6. 6 Play 'Double It' in pairs: flip a number card (1–10), first to say the double wins the card. Swap to 'Half It' with even number cards.
  7. 7 Students complete: double 7 = ___, half of 14 = ___, double ___ = 18, half of ___ = 4.

Tap a step to mark it as done.

Variations

  • Extend to doubling two-digit multiples of 5 (double 15, double 20)
  • Introduce near doubles (6+7 = double 6 + 1)
  • Use body doubles — each student finds a partner and they 'double' the group
More information

Display: 'Double ___ is ___.' / 'Half of ___ is ___.' Practise repeating in chorus. Ensure students understand 'equal' before halving.

Use a doubling machine diagram (input/output box) for visual learners. Restrict range to numbers 1–10 for those needing support.

Can students double without counting all? Do they understand halving as the inverse of doubling? Can they halve odd numbers and identify that halves are not always whole numbers?

Use fingers and toes. No materials required — all calculation done mentally or with body actions.

Students may think halving means 'cut it into any two pieces' rather than equal halves. Use the language 'two equal groups' consistently.

Activity details
Primary Easy 25 minutes 5 minutes prep Pairs, Whole Class Indoor & Outdoor
Topics
Doubling Halving Multiplication Division