New

New

Year 2

# Explain how doubling and halving are related

I can explain how doubling and halving are related.

New

New

Year 2

# Explain how doubling and halving are related

I can explain how doubling and halving are related.

## Lesson details

### Key learning points

- If double 4 is 8, then half of 8 is 4
- Halving means to partition the number into two equal groups.
- Halving is the inverse of doubling.
- Whether doubling or halving, we can also see these as our 2 times tables facts.

### Common misconception

Children may inaccurately recall related doubling facts to solve halving problems.

Represent each problem as a bar model (as the whole and two equal parts) before solving. Encourage children to check that the two equal parts are equal to the whole.

### Keywords

Double / Doubling - To become twice as many / to multiply by two.

Half / Halving - One of two equal parts of a whole. To divide into two equal parts.

Use the stem sentence, 'If I know ..., then I know ...' to help children see how doubling facts can help solve halving problems. Ensure children are encouraged to use this stem sentence when talking through their approach to a problem.

Teacher tip

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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## Starter quiz

Download starter quiz

### 6 Questions

Q1.

Which double is being shown here?

Double 4

Double 5

Q2.

Double 3 tens is ___

6

16

Q3.

Double 12 is

Q4.

Double 40 is

Q5.

Which of these equations could I use doubling knowledge to solve?

4 + 2 = ?

Q6.

What is 14 × 2 = ?

## Exit quiz

Download exit quiz

### 6 Questions

Q1.

Use the bar model to complete the sentence. Half of 8 is equal to

Q2.

If I know that half of 6 is equal to 3, then I know that _____________

double 4 is equal to 8

double 2 is equal to 4

Q3.

Which facts are represented by this bar model?

Double 4 is equal to 8

Half of 6 is equal to 3

Q4.

Which equation is represented by this bar model?

2 × 3 = 6

2 × 4 = 8

Q5.

Alex had 4 marbles. He gave half to Jacob. How many marbles did Jacob get? marbles

Q6.

Aisha gave half of her biscuits to Alex. Aisha was left with 6 biscuits. How many biscuits did Aisha have to begin with? biscuits