KS3 Maths · Year 7 · Chapter 4: Percentages · Lesson 1

Calculating percentages

Year 7About 60 minutesCalculator allowed52 marks

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Date

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Quick questions to start.

A1
Needed today
Write $\frac{3}{20}$ as a percentage.
[1 mark]
Answer
A2
Needed today
Write $0.375$ as a percentage.
[1 mark]
Answer
A3
Last lesson
A coin lands on heads $36$ times in $80$ throws. Estimate P(heads) as a decimal.
[1 mark]
Answer
A4
From chapter 2
One angle of a parallelogram is $6 5^{\circ}$ . Work out the size of an angle next to it.
[1 mark]
Answer

Year 7

Your teacher works through each example with you. Then try the one beside it.

Example 1

A cinema has $250$ seats. On Monday $185$ seats are sold. What percentage of the seats are sold?

Hint Write the amount as a fraction of the total, then change the fraction to a percentage.

B1
A school has $300$ pupils and $87$ of them walk to school. What percentage of the pupils walk to school?
[2 marks]
Answer

Example 2

Write $350$ g as a percentage of $2$ kg.

Hint Both amounts must be in the same units before you write the fraction.

B2
(i) Write $45$ cm as a percentage of $3$ m. (ii) Write $600$ ml as a percentage of $2.5$ litres.
[3 marks]
Answer(i) $\dots\dots$ (ii) $\dots\dots$

Example 3

Tom earns $£347.50$ a week. He spends $£92.40$ on travel. What percentage of his pay is that? Give your answer to the nearest whole number.

Hint Divide, then multiply by

100

. Round only at the end.

B3
A bag holds $2.75$ kg of rice. Ben uses $0.68$ kg. What percentage of the rice does he use? Give your answer to $1$ decimal place.
[2 marks]
Answer

Example 4

Last year a club had $240$ members. This year it has $312$ members. What percentage of last year's number is this year's number?

Hint "Of last year's number" means last year's number goes on the bottom of the fraction.

B4
Sam's sunflower was $48$ cm tall in May and $66$ cm tall in July. (i) Write the July height as a percentage of the May height. (ii) Write the May height as a percentage of the July height, to $1$ decimal place.
[3 marks]
Answer(i) $\dots\dots$ (ii) $\dots\dots$

Year 7

C1
In a survey of $80$ people, $28$ chose red, $36$ chose blue and the rest chose green. What percentage chose green?
[2 marks]
Answer
C2
A $400$ g packet of trail mix contains $140$ g of nuts. The rest is dried fruit. What percentage of the packet is dried fruit?
[2 marks]
Answer

C3
A swimming race is $1.5$ km. The pool is $25$ m long. What percentage of the race has Amy swum after $18$ lengths?
[2 marks]
Answer
C4
Ali sleeps for $8$ hours $24$ minutes in one day. What percentage of the day is that?
[2 marks]
Answer
C5
Jess scores $27$ goals from $45$ shots. Kat scores $38$ goals from $60$ shots. Who has the better success rate? Show your working.
[3 marks]
Answer

GCSE Foundation

D1
A suitcase weighs $18$ kg and its owner weighs $72$ kg. Priya says, "The suitcase is $25%$ of the total weight of the owner and the suitcase."
Is Priya correct? You must show your working.
[3 marks]

Stretch

No route is given. The hints are at the end of the sheet. Use one at a time.

Colour one circle on each line.

	Not yet	Nearly	Yes
I can write one amount as a percentage of another.
I can change amounts into the same units before I work out a percentage.
I can use a calculator to work out a percentage and round it.
I can work out percentages greater than 100%.

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