New
New
Year 7

Problem solving with fractions and ratios

I can use my knowledge of fractions and ratios to solve problems.

New
New
Year 7

Problem solving with fractions and ratios

I can use my knowledge of fractions and ratios to solve problems.

Lesson details

Key learning points

  1. Any fraction can be turned into a ratio.
  2. Moving between fractions and ratios can make a problem easier.
  3. There can be lots of information, it is important to think about what is required to solve the problem.

Common misconception

Always dividing the amount by the sum of the 'parts' of the ratio to get one 'part'.

Offer opportunities to match problems to bar models ensure the same numbers are used to highlight the differences.

Keywords

  • Proportion - Proportionality means when variables are in proportion if they have a constant multiplicative relationship.

  • Ratio - A ratio shows the relative sizes of 2 or more values and allows you to compare a part with another part in a whole.

As a recap of ratio, ask the pupils to come up with their ratios based on their own lives and the multiplicative relationship between them. E.g. The ratio of pets to people in their house, the ratio of matches their favourite team has won to lost.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
In this list of common metric units of length which one is missing? millimetre, centimetre, metre, .
Correct Answer: kilometre, km, kilometres, kilometer, kilometers
Q2.
1 km = 1000 m, 1 m = 100 cm. What is 5 400 000 cm in kilometres?
5400 km
540 km
Correct answer: 54 km
5.4 km
0.54 km
Q3.
The scale on a map is 1:5 000 000. The distance between two places on the map is 5 cm. What is the distance in real life in kilometres?
2.5 km
25 km
Correct answer: 250 km
2500 km
25 000 km
Q4.
The scale on a map is 1:500 000. The distance between two places is 86 km. What is the distance on the map?
Correct answer: 17.2 cm
172 cm
17.2 km
172 m
Q5.
The length of a pencil is 2.5 inches. Convert this into centimetres given that 1 inch = 2.54 cm.
Correct Answer: 6.35 cm, 6.35cm, 6.35, 6.35 centimetres, 6.35centimetres
Q6.
The distance between London and Manchester is 200 miles. Convert this into kilometres given that 5 miles = 8 km.
Correct Answer: 320 km, 320, 320km, 320 kilometres

6 Questions

Q1.
Fill in the missing word: Variables are in proportion if they have a multiplicative relationship.
Correct Answer: constant
Q2.
Select the bar model that is correctly labelled to solve this problem: Sam and Jacob share some stickers in the ratio of 3 : 7. Sam get 168 less than Jacob. How many stickers does Sam get?
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
Q3.
Sam and Jacob share some stickers in the ratio of 3 : 7. Sam get 168 less than Jacob. How many stickers does Sam get?
Correct Answer: 126, 126 stickers
Q4.
The ratio of children to adults in a club is 2 : 3. If there are 26 children, how many are in the club in total?
Correct Answer: 65, 65 people, sixty-five, sixty five, sixtyfive
Q5.
A bag contains red, green and yellow sweets. $$1\over4$$ of them are red. The rest of the sweets are either green or yellow, in the ratio 4 : 5. There are 72 sweets in the bag. How many are yellow?
Correct Answer: 30, 30 yellow , 30 yellow sweets, thirty
Q6.
Andeep’s older sister Belle is 3 times his age. His brother Charlie is $$5\over6$$ of Belle's age. The total of Andeep’s and Belle’s ages is 48. How old is Charlie?
Correct Answer: 30, 30 years old, thirty, thirty years old