### Planning and Activities

**Day 1**

Use two bead strings to show double 20. Remind children that doubling and halving are inverses. Stress that doubling is multiplying by 2 and halving is dividing by 2. Use ‘Mystery Machines’ (resources) alongside base-10 equipment to generate and discuss halves/doubles.**Further Teaching with Y1**

Use base-10 equipment to model the partitioning, doubling and recombining steps in doubling 10, 11, 12, 13 and 14.

**Group Activities: T with Y2**

Y1 -- Double handfuls of cubes.

-- Play a double numbers card game, using numbers up to 15.

Y2 -- Reason about the missing number or operation in ‘Mystery Machines’.

-- Play a double and half pairs game.

**Day 2**

Explain that halving is sharing the number between two. Demonstrate by sharing four sweets between two children. Repeat with other even numbers up to 20. Note that odd numbers need to be treated differently as there is always one left over. Display a bar model to show double 8 is 16. Use this to halve 16. Repeat for other numbers. Use base-10 equipment to support partitioning, halving and recombining.**Group Activities: T with Y2**

Y1 *Use the in-depth problem-solving investigation ‘Halving Chains’ as today’s group activity.* Or, use these activities:

-- Decide if numbers are odd or even, then halve the even numbers.

Y2 – Double and halve 2-digit numbers.