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Checking and securing understanding of real world ratios

I can apply my knowledge of ratios to real world contexts.

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Lesson 5 of 8

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Year 10

Checking and securing understanding of real world ratios

I can apply my knowledge of ratios to real world contexts.

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Lesson details

Key learning points

Bar models, ratio tables and double number lines can help with ratios.
Real-life scaling involves writing a ratio involving the parts which are dependent on each other.
A recipe is an example as to scale the recipe up or down requires keeping the proportions of the ingredients the same.

Keywords

Proportion - A part to whole (sometimes part to part) comparison. If two things are proportional then the ratio of part to whole is maintained and the multiplicative relationship between parts is also maintained.

Common misconception

Not converting the units correctly in a question or forgetting to have the same units before simplifying a ratio

help pupils to set out ratio tables where they include the units and work through step by step to convert correctly before simplifying. The ratio table can help organise this working.

Having a separate ratio table for converting the units can help.

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).

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Prior knowledge starter quiz

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6 Questions

Q1.
There are only red and green sweets in a bag. If the ratio of red to green is 4 : 7, what fraction of the sweets in the bag are red?

Correct answer: $$\frac{4}{11}$$

$$\frac{4}{7}$$

$$\frac{7}{4}$$

$$\frac{11}{4}$$

Q2.
There are only cars or bikes in a car park. If 40% are bikes, what is the ratio of cars : bikes?

Correct answer: 3 : 2

40 : 100

100 : 40

2 : 3

Q3.
There are only red, yellow and green marbles in a bag. $$\frac{1}{3}$$ are red, $$\frac{2}{5}$$ are yellow, write the ratio of red to yellow to green marbles.

Correct Answer: 5 : 6 : 4, 5:6:4

Q4.
A bag of sweets contains red, yellow and green sweets. There are 250 sweets in the bag. 30% of them are red. The rest are yellow and green in the ratio 3 : 4. How many green sweets are there?

Correct Answer: 100

Q5.
Laura and Sofia share some money in the ratio 2 : 7. Laura gives $$\frac{3}{8}$$ of her money to Jacob. If Jacob gets £33, how much does Sofia get?

Correct Answer: £308, 308

Q6.
Jacob, Andeep and Lucas receive some money. Jacob gets $$\frac{2}{7}$$ of the money. Andeep and Lucas share the rest in the ratio 4 : 7. What proportion of the prize money does Andeep get?

$$\frac{5}{7}$$

$$\frac{4}{11}$$

Correct answer: $$\frac{20}{77}$$

$$\frac{8}{77}$$

Assessment exit quiz

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6 Questions

Q1.
Select the units of measure that are metric.

inches

Correct answer: centimetre

Correct answer: millilitres

miles

Correct answer: grams

Q2.
A recipe for a stir-fry uses 30 ml of soy sauce. The recipe is for 4 people. How many millilitres of soy sauce would you need to make the recipe for 12 people?

Correct Answer: 90, 90 ml, 90ml

Q3.
A recipe for a stir-fry uses 36 ml of soy sauce. The recipe is for 6 people. How many millilitres of soy sauce would you need to make the recipe for 10 people?

Correct Answer: 60, 60 ml, 60ml

Q4.
A recipe for soup for 8 people uses 200 g of carrots. Andeep is making the soup for more people and has correctly scaled the recipe. He is using 375 g of carrots. How many people will this serve?

Correct Answer: 15

Q5.
A scale on a map is 1 : 250 000. How long would something that measured 3 cm on the map be in real life?

Correct answer: 7.5 km

7.5 cm

750 000 m

750 000 km

Q6.
A scale on a map is 1 : 50 000. How long would something that is 4 km in real life measure on the map?

Correct answer: 8 cm

200 000 cm

2 m

0.08 cm

8 km

Lesson appears in

UnitMaths / Ratio

Maths

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Checking and securing understanding of real world ratios

Checking and securing understanding of real world ratios

Lesson slides

Lesson details

Key learning points

Keywords

Common misconception

Licence

Lesson video

Worksheet

Prior knowledge starter quiz

6 Questions

Q1.There are only red and green sweets in a bag. If the ratio of red to green is 4 : 7, what fraction of the sweets in the bag are red?

Q2.There are only cars or bikes in a car park. If 40% are bikes, what is the ratio of cars : bikes?

Q3.There are only red, yellow and green marbles in a bag. $$\frac{1}{3}$$ are red, $$\frac{2}{5}$$ are yellow, write the ratio of red to yellow to green marbles.

Q4.A bag of sweets contains red, yellow and green sweets. There are 250 sweets in the bag. 30% of them are red. The rest are yellow and green in the ratio 3 : 4. How many green sweets are there?

Q5.Laura and Sofia share some money in the ratio 2 : 7. Laura gives $$\frac{3}{8}$$ of her money to Jacob. If Jacob gets £33, how much does Sofia get?

Q6.Jacob, Andeep and Lucas receive some money. Jacob gets $$\frac{2}{7}$$ of the money. Andeep and Lucas share the rest in the ratio 4 : 7. What proportion of the prize money does Andeep get?

Assessment exit quiz

6 Questions

Q1.Select the units of measure that are metric.

Q2.A recipe for a stir-fry uses 30 ml of soy sauce. The recipe is for 4 people. How many millilitres of soy sauce would you need to make the recipe for 12 people?

Q3.A recipe for a stir-fry uses 36 ml of soy sauce. The recipe is for 6 people. How many millilitres of soy sauce would you need to make the recipe for 10 people?

Q4.A recipe for soup for 8 people uses 200 g of carrots. Andeep is making the soup for more people and has correctly scaled the recipe. He is using 375 g of carrots. How many people will this serve?

Q5.A scale on a map is 1 : 250 000. How long would something that measured 3 cm on the map be in real life?

Q6.A scale on a map is 1 : 50 000. How long would something that is 4 km in real life measure on the map?

Lesson appears in

UnitMaths / Ratio

Maths

Q1.
There are only red and green sweets in a bag. If the ratio of red to green is 4 : 7, what fraction of the sweets in the bag are red?

Q2.
There are only cars or bikes in a car park. If 40% are bikes, what is the ratio of cars : bikes?

Q3.
There are only red, yellow and green marbles in a bag. $$\frac{1}{3}$$ are red, $$\frac{2}{5}$$ are yellow, write the ratio of red to yellow to green marbles.

Q4.
A bag of sweets contains red, yellow and green sweets. There are 250 sweets in the bag. 30% of them are red. The rest are yellow and green in the ratio 3 : 4. How many green sweets are there?

Q5.
Laura and Sofia share some money in the ratio 2 : 7. Laura gives $$\frac{3}{8}$$ of her money to Jacob. If Jacob gets £33, how much does Sofia get?

Q6.
Jacob, Andeep and Lucas receive some money. Jacob gets $$\frac{2}{7}$$ of the money. Andeep and Lucas share the rest in the ratio 4 : 7. What proportion of the prize money does Andeep get?

Q1.
Select the units of measure that are metric.

Q2.
A recipe for a stir-fry uses 30 ml of soy sauce. The recipe is for 4 people. How many millilitres of soy sauce would you need to make the recipe for 12 people?

Q3.
A recipe for a stir-fry uses 36 ml of soy sauce. The recipe is for 6 people. How many millilitres of soy sauce would you need to make the recipe for 10 people?

Q4.
A recipe for soup for 8 people uses 200 g of carrots. Andeep is making the soup for more people and has correctly scaled the recipe. He is using 375 g of carrots. How many people will this serve?

Q5.
A scale on a map is 1 : 250 000. How long would something that measured 3 cm on the map be in real life?

Q6.
A scale on a map is 1 : 50 000. How long would something that is 4 km in real life measure on the map?