Short Blocks

Maths Year 1/2 Summer Multiplication and Division (B)

Each unit has everything you need to teach a set of related skills and concepts.

Doubling and halving (suggested as 2 days)

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.

You Will Need

  • Cubes
  • ‘Mystery Machine’ Sheets A, B and C (see resources)
  • Mini-whiteboards and pens
  • ‘Doubling recording sheet’ (see resources)
  • ‘Doubling cards’ Sheets 1–3 (see resources)
  • ‘Doubling recording sheet’ (see resources)
  • Number cards 1–40
  • Blank cards
  • ‘Mystery Machine doubling and halving’ Sheets 1 and 2 (see resources)
  • Blank ‘Mystery machine doubling and halving’ sheets (see resources)
  • Calculators
  • Sticky notes
  • ‘Halving’ (see resources)
  • ‘Halving recording sheet’ (see resources)
  • Base-10 equipment, e.g. Dienes blocks or number shapes
  • 20-bead (or 100-bead) strings

Short Mental Workouts

Day 1
Doubling numbers to 10

Day 2
Odd/even numbers

Worksheets

Day 1
Y1: Double numbers to 15; record as an addition sentence.
Double numbers to 21; record as an addition sentence.
Y2: Reason about the missing number or operation in doubling/halving Mystery Machines.

Day 2
Y1: Halve numbers to 22 or 32.
Y2: Halving investigation.

Mastery: Reasoning and Problem-Solving

Y1

  • Draw lines from each double to its matching half
    14 6
    12 10
    16 7
    28 8
    20 13
    24 14
    26 12
  • Double 3, double the answer, and double the answer.
    Halve 28 and halve the answer. Is the answer more than 10?

    Y2
  • Write the missing halves/doubles (see download).
  • Poppy starts at 56 and keeps halving. What is the first 1-digit number she reaches?

In-depth investigation: Halving chains
Children investigate which numbers from 1 to 20 (Y1) or 1 to 50 (Y2) will give the longest halving chain (each 'link' must be a whole number).

Extra Support

Y1: Copycat
Finding doubles from double 1 to double 10
AND
Be Fair!
Halving even numbers up to 10

Y2: Double your money
Doubling 11 to 20
AND
Fair or not fair
Halving even numbers from 20 to 30