# Maths Year 4 Autumn Multiplication and Division

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

## Double and halve 2- and 3-digit numbers(suggested as 2 days)

### Planning and Activities

Day 1 Teaching
Display 26 and model how to draw a jotting to partition:

Double 26
/ \
40 12
40 + 12 = 52

Demonstrate how the same jotting will help us partition a number to halve it. Repeat with other numbers.
Group Activities
Use the ‘Doubling Forever’ in-depth problem-solving investigation below as today’s group activity.
Or, use these activities:
Find double and half of odd and even 2-digit numbers.

Day 2 Teaching
Write 226 and draw a partitioning jotting to show children how to double this number. The same process can be modelled for halving. Demonstrate how the jotting is crucial (we use it to partition the numbers).
Group Activities
Use doubling to check halving answers.
Double and halve 3-digit numbers.

### You Will Need

• Place value dice or 0–9 digit cards
• Whiteboards
• Flipchart
• Place value equipment

### Mental/Oral Maths Starters

Day 1
Double the numbers 1 to 20 and find the corresponding halves (pre-requisite skills)

Day 2
Double and halve multiples of 100 (pre-requisite skills)

### Worksheets

Day 1
Use bar models to find pairs of doubling and halving facts.

Day 2
Double and halve 3-digit numbers.

### Mastery: Reasoning and Problem-Solving

• Write two sentences to relate three of these numbers: 2, 37, 74 and 148.
• Use a jotting to double these numbers:
a) 216
b) 327
c) 438
Can you describe a pattern in the answers?
• We know double 30 is 60 and double 8 is 16.
So, what half of 76?
• Explain in one sentence why a jotting helps us find half of 318.

In-depth Investigation: Doubling forever
Children double numbers up to 20 and look for duplicate sequences.

### Extra Support

Double or Halve?
Doubling and halving 2-digit numbers using partitioning (whole number answers only)