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New
Converting units of length
I can use knowledge of multiplication and division to convert units of length.
Lesson 4 of 15
New
New
- Year 5
Converting units of length
I can use knowledge of multiplication and division to convert units of length.
Lesson details
Key learning points
- There are 10 mm in 1 cm.
- There are 100 cm in 1 m.
- There are 1,000 m in 1 km.
- There are 1,000 mm in 1 m.
- There are 10 dm in 1 m.
Keywords
Convert - To convert means to change a value or expression from one form to another. In this context it means to change from one unit of measurement to another such as from cm to mm.
Decimetre - A decimetre is a metric unit of length, equal to one-tenth of a metre. Decimetre can be abbreviated to dm.
Common misconception
Children may confuse when to multiply or when to divide.
Encourage children to think about which unit of measure is larger e.g. km are larger than m. In a given amount, there will be fewer of the larger unit so we need to divide.
Give children chance to practice measuring in one unit and converting to the other given units. Children need to be secure in multiplying and dividing by 10 and its powers to avoid overload when converting between measures.
Teacher tip
Licence
This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match the expression to their product.
Match the expression to their product.
Q2.13.09 x 10 = ?
13.09 x 10 = ?
13.090
13.9
139
1309
Q3.When we multiply 0.72 by 100, what is the new value of the digit 7?
When we multiply 0.72 by 100, what is the new value of the digit 7?
seven hundredths
seven tenths
seven ones
seven hundreds
Q4.Match the expression to the correct product.
Match the expression to the correct product.
Q5.Lucas is thinking of a number. His number is one hundredth times the size of 4 What is his number?
Lucas is thinking of a number. His number is one hundredth times the size of 4 What is his number?
0.004
0.4
40
40
Q6.What is the perimeter of a rectangular field of length 350 m and width 250 m? m.
What is the perimeter of a rectangular field of length 350 m and width 250 m? m.
Assessment exit quiz
6 Questions
Q1.Match the equivalent lengths
Match the equivalent lengths
Q2.Match the equivalent lengths.
Match the equivalent lengths.
Q3.Which of these is the correct conversion of 9,035 m into km?
Which of these is the correct conversion of 9,035 m into km?
9,035 m × 1,000 = 9,035,000 km
9,035 m ÷ 1,000 = 0.935 km
9,035 m ÷ 1,000 = 0.9035 km
9,035 m ÷ 100 = 90.35 km
Q4.True or false? A line measuring 104 mm is longer than a line measuring 11 cm.
True or false? A line measuring 104 mm is longer than a line measuring 11 cm.
True
Q5.Starting with the smallest, put these measurements in order.
Starting with the smallest, put these measurements in order.
Q6.The width of a rectangular lake is 700 m and the length is 0.91 km. What is the perimeter of the lake? Give your answer in kilometres. km
The width of a rectangular lake is 700 m and the length is 0.91 km. What is the perimeter of the lake? Give your answer in kilometres. km
