New
New
Year 5

# Describe changes in measurement using knowledge of multiplication and division

I can describe changes in measurement using knowledge of multiplication and division.

New
New
Year 5

# Describe changes in measurement using knowledge of multiplication and division

I can describe changes in measurement using knowledge of multiplication and division.

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## Lesson details

### Key learning points

1. Many things change and we need to describe the change mathematically.
2. The sentence 'The __________ is ___ times the __________ of the __________' supports understanding.
3. A change in measurement can be described multiplicatively.
4. Division can be represented as multiplication by a unit fraction

### Common misconception

Children are more familiar with multiplication resulting in an increase, and need to appreciate that it can also result in a decrease.

When we multiply an integer by a unit fraction, the effect is the same as dividing the whole by the denominator. It results in a decrease.

### Keywords

• Change - A comparison can be made between an object at the start of, and then after, a change. Examples of change include a change in mass of an animal due to growth.

It is important that children are fluent with their times table facts so they can focus on the scaling structure without overload. Always offer practical examples where possible.
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).

## Starter quiz

### 6 Questions

Q1.
Jacob and Sam both walk to school. It takes Izzy 18 minutes. It takes Sam one sixth times as long. Does this table represent the times?
Yes
Q2.
Jacob and Sam both walk to school. It takes Izzy 18 minutes. It takes Sam one sixth times as long. It takes Sam minutes to walk to school
Q3.
Izzy plays the whole 90 minutes of a football match but Jacob has to leave after one third of the match. How long did Jacob play for? Jacob played for minutes.
Q4.
Sam saved £120. Jacob saved one quarter times as much money as Sam. Which representation shows this?
Correct Answer: An image in a quiz
Q5.
Sam saved £120. Jacob saved one quarter times as much money as Sam. Which calculations would you need to work out how much money Jacob and Sam saved together?
£120 × 4 =
Correct answer: £120 × $${1}\over{4}$$ =
£120 + £4 =
Correct answer: £120 + £30 = £150
Q6.
Match the amounts of money that Sam and Jacob might have saved from the information in the table.
Correct Answer:Sam saved £3.60,Jacob saved £1.20

Jacob saved £1.20

Correct Answer:Jacob saved £3.50,Sam saved £10.50

Sam saved £10.50

Correct Answer:Sam saved £12,Jacob saved £4

Jacob saved £4

Correct Answer:Jacob saved £12,Sam saved £36

Sam saved £36

Correct Answer:Sam saved £21,Jacob saved £7

Jacob saved £7

## Exit quiz

### 6 Questions

Q1.
An iceberg has melted to one quarter of its original mass. It was 1,600 kg. Which table represents this?
Correct Answer: An image in a quiz
Correct Answer: An image in a quiz
Q2.
An iceberg has melted to one quarter of its original mass. It was 1,600 kg. Which calculation would you need to work out the new mass of the iceberg?
1,600 kg × 4 =
1,600 × 4 kg =
Correct answer: 1,600 kg ÷ 4 =
1,600 ÷ 4 kg =
Q3.
An iceberg has melted to one quarter of its original mass. It was 1,600 kg. The new mass of the iceberg is kg.
Correct Answer: 400, four hundred, Four hundred
Q4.
Jacob had £250 when he opened his bank account. Now he has one tenth times his original amount. Which fraction is missing from the arrow in the table?
$${1}\over{2}$$
$${1}\over{5}$$
Correct answer: $${1}\over{10}$$
$${10}\over{1}$$
Q5.
Jacob had £250 when he opened his bank account. Now he has one tenth times his original amount. How much money has Jacob spent?
£250
£25
£125