# www mathsrevision com Percentages Revision of Level E

• Slides: 26

www. mathsrevision. com Percentages Revision of Level E Appreciation / Depreciation Expressing “A” as a percentage of “B” Finding Initial Value after increase or decrease 11/21/2020 Created by Mr. Lafferty Maths Dept.

www. mathsrevision. com Starter Questions Q 1. 34. 5 + 0. 6 + 5 Q 2. Tidy-up the expression Q 3. Q 4. 11/21/2020 Created by Mr. Lafferty Maths Dept.

Percentages www. mathsrevision. com Revision of Level E Learning Intention 1. To summarise Level E work using Mind Map. Success Criteria 1. Convert percentages to fractions and decimals. 2. Change fraction to percentages. 3. Find percentage values. 11/21/2020 Created by Mr. Lafferty Maths Dept.

Percentages www. mathsrevision. com Revision of Level E 11/21/2020 Put over 100 3 Put over 100 7 Created by Mr. Lafferty Maths Dept.

www. mathsrevision. com What simple % is missing Percentages 80% = Revision of Level E Example : Find 20% of £ 450 11/21/2020 Created by Mr. Lafferty Maths Dept.

How to find % of a quantity using a calculator S 3 www. mathsrevision. com example Find Step 1 : Convert % to a decimal of means x Step 2 : Step 3 : Do sum Calculator Keys 5 0 11/21/2020 1 0 0 x 3 0 Created by Mr. Lafferty Maths Dept. 0 = 150

How to find % of a quantity using a calculator S 3 www. mathsrevision. com example Find Step 1 : Convert % to a decimal of means x Step 2 : Step 3 : Do sum Calculator Keys 4 0 11/21/2020 1 0 0 x 4 8 Created by Mr. Lafferty Maths Dept. 0 = 192

Percentages www. mathsrevision. com Revision of Level E Now try Exercise 1 Ch 19 (page 92) 11/21/2020 Created by Mr. Lafferty Maths Dept.

www. mathsrevision. com Starter Questions 5 cm 11/21/2020 Created by Mr. Lafferty Maths Dept. 6 cm

Calculating Percentages www. mathsrevision. com Appreciation & Depreciation Learning Intention 1. To understand the terms appreciation and depreciation. Success Criteria 1. To know the terms appreciation and depreciation. 2. Show appropriate working when solving problems containing appreciation and depreciation. 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Appreciation & Depreciation Appreciation / Depreciation Appreciation : Going up in value e. g. House value Depreciation : Going down in value e. g. car value 11/21/2020 Created by Mr. Lafferty Maths Dept.

Average house price in Glasgow has appreciated by 50% over the past 10 years. If you bought the house for £ 80 000 in 1994 how much would the house be worth now ? Appreciation = 50% x £ 80 000 = 0. 50 x £ 80 000 = £ 40 000 New value = Old Value + Appreciation = £ 80 000 + £ 40 000 = £ 120 000 11/21/2020 Created by Mr. Lafferty Maths Dept. Just working out percentages

Calculating Percentages www. mathsrevision. com Appreciation & Depreciation A Mini Cooper cost £ 15 000 in 2005 At the end 2006 it will have depreciated by 20% What will the mini cooper worth at end 2006? End 2006 Depreciation = 20% x £ 15 000 = 0. 2 x £ 15 000 = £ 3 000 New value = Old value - Depreciation = £ 15 000 - £ 3000 = £ 12 000 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages Appreciation & Depreciation A valuable piece of jewellery appreciated by 10% in the 1 st year and by 20 % in the 2 nd Year. If its initial value was £ 1 000, what is its value now ? 1 st Year Appreciation = 10% x £ 1 000 = 0. 1 x £ 1 000 = £ 100 New Value = £ 1 000 + £ 100 = £ 1 100 2 nd Year Appreciation = 20% x £ 1 100 = 0. 2 x £ 1 100 = £ 220 New Value = £ 1 100 + £ 220 = £ 1320 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Appreciation & Depreciation Now try Exercise 2 Ch 19 (page 94) 11/21/2020 Created by Mr. Lafferty Maths Dept.

www. mathsrevision. com Starter Questions 10 cm 11/21/2020 Created by Mr. Lafferty Maths Dept. 8 cm

Calculating Percentages www. mathsrevision. com Expressing “A” as a percentage of “B” Learning Intention 1. To understand how to express “A” as a percentage of “B”. Success Criteria 1. To understand how to express “A” as a percentage of “B”. 2. Solve problems in context. 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Expressing “A” as a percentage of “B” Example 1 : Frances scored 13 out of 20 in a Maths test. What was her percentage score? A % mark = B 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages Expressing “A” as a percentage of “B” Example 2 : Daniel was paid £ 20 per week. He got a wage rise to £ 22 per week. What was his percentage increase in pay ? A Actual Increase = £ 22 - £ 20 = £ 2 % increase = B 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages Expressing “A” as a percentage of “B” Example 3 : A house in Barlanark bought for £ 40 000 in 2001 was sold last week for £ 50 000. Calculate the percentage appreciation in value? A Actual Increase = £ 50 000 - £ 40 000 = £ 10 000 % increase = B 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Expressing “A” as a percentage of “B” Now try Exercise 3 Ch 19 (page 97) 11/21/2020 Created by Mr. Lafferty Maths Dept.

www. mathsrevision. com Starter Questions 11/21/2020 Created by Mr. Lafferty Maths Dept.

Percentages www. mathsrevision. com Finding initial value after an increase or decrease Learning Intention 1. To explain how to find the initial value after an increase or decrease. Success Criteria 1. To understand the process of finding the initial value. 2. To solve problems using this process. 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Finding initial value after an increase or decrease Example 1 After a 10% increase the price of a house is £ 88 000. What was the price before the increase. Deduce from question : 100 % + 10 % = £ 88 000 We have : 110 % = £ 88 000 1%: Price before is 100% : £ 800 x 100 = £ 80 000 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Finding initial value after an increase or decrease Example 2 The value of a car depreciated by 20%. It is now valued at £ 2550. What was it’s original price. Deduce from question : 100 % - 15 % = £ 2 550 We have : 85 % = £ 2 550 1%: Price before is 100% : £ 30 x 100 = £ 3 000 11/21/2020 Created by Mr. Lafferty Maths Dept.

Calculating Percentages www. mathsrevision. com Finding initial value after an increase or decrease Now try Exercise 4 Ch 19 (page 98) 11/21/2020 Created by Mr. Lafferty Maths Dept.