The reciprocal is the multiplicative inverse of any non-zero number. Any non-zero number multiplied by its reciprocal is equal to 1

Deepening understanding with fractions of a given amount

Maths

The multiplicative relationship is extended in the future unit by considering percentages and the connections between multiplicative relationships and direct proportion. By building on a secure understanding of fractions and ratio, pupils can see their understanding of multiplicative relationships being extended.

In the prior unit, pupils generalised and developed their fluency of multiplying with fractions. In this unit, this understanding is extended to ratio and connections between ratios and fractions are explored.

Understanding multiplicative relationships: fractions and ratio

Match the following to the correct reciprocal.

A shop has a sale saving you $$1\over3$$ off the original price.  You pay £40 for a sweatshirt.  How much was it originally?

$$1\over5$$ of 60 = $$4\over5$$ of $$\square$$.

I think of a number.  $$3\over8$$ of my number is 15.  What is my number?

The cost of a TV increases by $$1\over8$$.  It now costs £450.  How much was it originally?

Alex's cat loses $$1\over6$$ of it's weight.  It now weighs 4.2 kg, how heavy was it last year?

Which of the following is not the reciprocal of 3?

Use a bar model to calculate $$5\over8$$ of 32.

Which of the following are equivalent calculations for $$5\over6$$ of 66?

Calculate $$3 {{3} \over {4}}$$ × $$5\over6$$, give your answer in its simplest form.

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Deepening understanding with fractions of a given amount

Lesson outcome