1. GCSE Maths

3. What are we going to do this week?
Ratio
Use ratio notation
Simplify ratios
Divide a given quantity into parts
Find amounts given parts of a ratio
Proportion
Understand and use proportion
Solve problems involving proportion
Ratio, Proportion, Fractions, Decimals and Percentages
Link ratio, proportion, fractions, decimals and percentages

4. What is ratio? Ratio is a way of comparing amounts of something.
It shows how much bigger one thing is than another.

5. How is ratio written?
4 : 1
This ratio has 5 parts altogether as = 5.
This will be important a bit later on!

9. What fraction of the shapes are triangles?

10. Which can be simplified to:
Simplifying Ratios
The ratio of blue to yellow blocks is
blue : yellow = 4 : 2
Which can be simplified to:
4 : 2 ÷2 ÷2
2 : 1

11. 1 : 2
2 : 3
1 : 3
1 : 2
2 : 9
1 : 2
7 : 5
2 : 3
1 : 2
4 : 5
2 : 5

12. When writing ratio, they must first be converted to the same unit.
Write the ratios in their simplest form
1mm : 5cm (b) £3.50 : 70p
15 mins : hour (d) 2mm : 10mm
(e) 5.2 litres : 300cl
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13. Expanding ratio

14. Now you try…

15. Share €10 between Mandy and Lara in the ratio 3 : 2
Number of equal parts = = 5 2 2 2 2 2 2 2 2 2 2
Amount in 1 part = 10 ÷ 5 = € 2
Mandy gets = € 2  3 = € 6
Lara gets = € 2  2 = € 4

16. Number of equal parts = 4 + 3 = 7
A 35 ml orange drink is made by mixing orange juice and water in the ratio 4 : 3.
Number of equal parts = = 7 5 5 5 5 5 5 5 5 5 5 5 5 5 5
Amount in 1 part = 35 ÷ 7 = 5 ml
Orange Juice = 5  4 = 20 ml
Water = 5  3 = 15 ml

17. More wordy question…your turn

18. How would you do these?
Work in pairs/small groups, discuss how you would do this question.
Prepare to feed your discussion back to the group

19. Applying skills
Apply a technique you feel most comfortable with to answer questions. To get good at maths you must do maths!!

20. Back to targets
Can you now use probability vocabulary, write probabilities as fractions, decimals or percentages?

21. Lesson 2
Proportion

23. Proportion
This involves things such as recipes, where the mix has to be in multiples to be correct. It is similar to sharing in a ratio. Everything must be multiplied or divided by the same amount to keep all the parts in proportion.

24. How many portions?
What we know

25. Proportion
A recipe to make 4 cup cakes requires the following ingredients:
2 eggs
250g of flour
100g of sugar
How much of each ingredient would I need to make 10 cup cakes?

26. Proportion
A fruit punch for 20 glasses requires the following ingredients:
1 litre of orange juice
600ml of apple juice
250ml of cranberry juice
350ml of grapefruit juice
I need to make enough for 75 glasses of fruit punch.
How much of each ingredient do I need?

27. Past paper question – 3 marks

28. Hint…how much of the original has Oliver got?
A trickier problem…
Hint…how much of the original has Oliver got?

29. Applying skills
Apply a technique you feel most comfortable with to answer questions. To get good at maths you must do maths!!

30. Back to targets
Can you now use probability vocabulary, write probabilities as fractions, decimals or percentages?