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Find the whole when the size of a unit fraction is known

I can find the whole when the size of a unit fraction is known.

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Lesson 8 of 10

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Year 5

Find the whole when the size of a unit fraction is known

I can find the whole when the size of a unit fraction is known.

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Key learning points

The whole has been divided into __ equal parts and this is one of the parts.
There will be __ of these parts in the whole.
The whole is __ times the size of this part.
If you know the size of a unit fraction, you can work out the size of the whole.

Keywords

Unit fraction - A unit fraction is a fraction that has a numerator of one.
Denominator - The denominator is the number on the bottom of a fraction. It tells us how many parts the whole has been divided into.

Common misconception

When a unit fraction is represented as a quantity greater than one, pupils may think each part of the unit fractions quantity is itself the unit fraction of the whole.

Draw a circle around the quantity each time to encourage pupils to recognise that each set of objects is representative of a quantity that is one part of the whole.

Provide opportunities for pupils to present their thinking practically. It may be useful to use equal-sized shapes (counters/cubes) to allow pupils to recreate the wholes based on the size of the unit fraction.

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