Scale a decimal measure
3 ribbons each 1.5 m long measure 4.5 m altogether.
Equal groups often mean multiplication.
Year 5
Use all four operations to solve problems involving measure using decimal notation, including scaling
Use all four operations to solve measure problems involving decimal notation and scaling.
Lesson overview
Time
Some measure problems use decimal values such as 1.5 m or 2.75 l. We solve them by deciding which operation fits the context and by keeping the decimal places lined up carefully.
Share a decimal amount
4.8 litres shared equally into 6 jugs gives 0.8 litres each.
Division can show an equal share.
Compare decimal measures
6.25 m is 0.75 m more than 5.5 m.
Line the decimal places up before subtracting.
Worked example
A roll of fabric is 2.4 m long. Four rolls are bought. How much fabric is that altogether?
- Each roll has the same length.
- Multiply 2.4 by 4.
- 2 x 4 is 8 and 0.4 x 4 is 1.6.
- The total length is 9.6 m.
Round 1: Learn it
Decide which operation matches the measure story before you calculate.
Finish this round to unlock Round 2: Show you know it.
Question 1
3 ribbons each 1.5 m long have total length?
Question 2
4.8 litres shared into 6 equal jugs gives how much in each jug?
Question 3
What is 6.25 m - 5.5 m?
Question 4
A roll is 2.4 m long. Four rolls give how many metres altogether?
Question 5
Which operation best fits 7.2 litres shared equally between 8 bottles?
Common mistakes
Watch for these as you work through the lesson.
- Using the wrong operation for the context.
- Ignoring the decimal point when adding or subtracting.
- Forgetting that scaling means repeated equal groups.
Related topics
These ideas connect closely to this lesson.
- Convert between different units of time.
- Solve problems involving converting between units of time and using timetables.