Describe changes in measurement using knowledge of multiplication and division | Maths

Starter quiz

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
- No ✓
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
- '3' ✓
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.
- '30' ✓
Sam saved £120. Jacob saved one quarter times as much money as Sam. Which representation shows this?
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 =
- £120 × ${1}\over{4}$ = ✓
- £120 + £4 =
- £120 + £30 = £150 ✓
Match the amounts of money that Sam and Jacob might have saved from the information in the table.
- Sam saved £3.60
  
  ⇔
  
  Jacob saved £1.20 ✓
- Jacob saved £3.50
  
  ⇔
  
  Sam saved £10.50 ✓
- Sam saved £12
  
  ⇔
  
  Jacob saved £4 ✓
- Jacob saved £12
  
  ⇔
  
  Sam saved £36 ✓
- Sam saved £21
  
  ⇔
  
  Jacob saved £7 ✓

An iceberg has melted to one quarter of its original mass. It was 1,600 kg. Which table represents this?
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 =
- 1,600 kg ÷ 4 = ✓
- 1,600 ÷ 4 kg =
An iceberg has melted to one quarter of its original mass. It was 1,600 kg. The new mass of the iceberg is ______ kg.
- '400' ✓
$Jacob had £250 when he opened his bank account. Now he has one tenth times his original amount. Which fraction is missing from the arrow in the table?$

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?
- ${1}\over{2}$
- ${1}\over{5}$
- ${1}\over{10}$ ✓
- ${10}\over{1}$
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
- £225 ✓
Sam had £15. Now she has £60. How many times the original amount does she have now? Sam has ______ times the original amount.
- '4' ✓

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

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.

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.