7. ES: Application of Number: Percentages

AON: Percentages

1. PERCentages Application of Number Unit 1 Leigh McQuaid

2. Learning Intentions Understand what the term ' percent' means Understand the 2-step method for finding percentages of an amount. Increase and decrease amounts by a given percentage Write percentages of an amount using knowledge of fractions and conversions

3. Percentage of an amount If we know that percentage is always out of 100, we can write percentages as fractions. Eg. 15% of 60 = 15 / 100 of 60 Now use your knowledge of fractions to work out the answer 60 ÷ 100 x 15 = 9

4. Percentage of an amount Think of the percentage as a fraction (divide by bottom, times by top) Find 66% of 78 78 ÷ 100 x 66 = 51.48 Find 45% of 950 950 ÷ 100 x 45 = 427.5

5. Percentage of an amount on a calculator Another way of working out percentages is to use your calculator and multiply Find 66% of 78 66% x 78 = 51.48 Find 45% of 950 45% x 950 = 427.5 On the CASIO calculators, press the 'catalogue' button and select 'probability' to find the percentage sign

6. Percentage of an amount on a calculator Practice both methods on the following calculations: 13% of 500         6. 24% of 1400 12% of 800         7. 32% of 800 23% of 600         8. 38% of 1300 26% of 700         9. 31% of 300 28% of 900         10. 35% of 600

7. Complete part 1 of the page entitled 'Percentages'

8. Increase vs decrease Increase means the size or amount of something goes UP or gets BIGGER Decrease means the amount of something goes DOWN or gets SMALLER Words that suggest something is getting bigger: Increase Rise Grow Tax VAT Words that suggest something is getting smaller: Decrease Lower Drop Discount Sale

9. Percentage increase Find the percentage of the amount using one of the methods from earlier. In these examples, we are looking at an increase, so ADD your answer to the first step from the original amount in the question A bottle of shampoo is £22.50 excluding VAT. If VAT is 20%, what should the price be including VAT?

10. Percentage increase Find the percentage of the amount using one of the methods from earlier. In these examples, we are looking at an increase, so ADD your answer to the first step from the original amount in the question A jar of coffee which is normally 500g is advertised as being 'Special Edition – 35% extra'. How much coffee is in the jar?

11. Percentage Decrease Find the percentage of the amount using one of the methods from earlier. In these examples, we are looking at an decrease, so TAKE AWAY your answer from to the first step from the original amount in the question A bar is selling drinks on offer 'Buy two, get the third 25% off'. If the drinks cost £4.80, how much is the third drink?

12. Percentage Decrease Find the percentage of the amount using one of the methods from earlier. In these examples, we are looking at an decrease, so TAKE AWAY your answer from to the first step from the original amount in the question A bill for restyles and foils for two bridesmaids comes to £220. The customer has a voucher for 10% discount. How much is the discount and what is the new price? 10% of £220 = £22   (discount) £220 - £22 = £198   ( new price )

13. QUIZ TIME https://wordwall.net/play/88079/682/604

14. Writing percentages of an amount Write the number as a fraction first. 2. Convert the fraction into a percentage (top ÷ bottom x 100) Eg. You are collecting data in your salon, you find that in one day, you had 44 clients and 11 of those were male. What percentage were male?   11 / 44    11 ÷ 44 x 100 = 25%

15. Writing percentages of an amount Write the number as a fraction first – Remember the total (bigger) number always goes on the bottom. Convert the fraction into a percentage (top ÷ bottom x 100) Eg. You have started a mobile catering company and want to advertise in the local newspaper. An advert usually costs £80 but they have agreed to do it for £32 because you are a new business. What percentage did you save?  Step 1:  How much did you save?  Step 2:  Write as a fraction  48 / 80  (80 was the total price originally)  Step 3:  Convert to a percentage  48 ÷ 80 x 100 = 25%

16. Complete part 2 and 3 of the page entitled 'Percentages'

17. Remember Top ÷ bottom x 100 % over 100 simplify ÷ 100

18. Learning Intentions Understand what the term ' percent' means Understand the 2-step method for finding percentages of an amount. Increase and decrease amounts by a given percentage Write percentages of an amount using knowledge of fractions and conversions

19. Answers

20. 65             6. 336 96             7. 256 138             8. 494 182             9. 93 252             10. 210