Percentages Objectives: D Grade Express one quantity as

Percentages Objectives: D Grade Express one quantity as a percentage of another Prior knowledge: Understand how to: Convert fractions to equivalent fractions Convert fractions to decimals Convert decimals to percentages Percentages What is a percentage? percent out of hundred So we can think of percentages also as fractions with a denominator of 100: This helps us to understand that e.g. 65 percent finding a percentage of a quantity 65 is the same as finding a fraction of a per 000

0 quantity cent Percentages Expressing one quantity as a percentage of another Compare one quantity with the other. e.g. compare 20 with 25 Write: compare with 20 25 Write as an equivalent fraction with the denomination 100 20 25 This is now 80% 80 100 because 80 is the same as 80%

100 Percentages Sometimes you might need to have an intermediate equivalent fraction e.g. compare 4 with 40 4 40 Simplify as an equivalent fraction Write: compare with 4 40 1 10 Now write as an equivalent fraction with the denominator of 100 1 10 10 100 This is now 10%

because 10 is the same as 10% 100 Percentages Now do these: 1. Write 4 as a percentage of 20 2. Write 50 as a percentage of 200 3. Write 14 as a percentage of 28 4. Write 4 as a percentage of 25 5. Write 18 as a percentage of 45

4 20 50 200 21 28 4 25 18 45 20 100 25 100 3 10 4 100 16 100

2 40 5 100 Percentages Harder percentages of quantities can be found using a calculator. compare with 24 34 can be read as Convert from a fraction to a decimal: Using a calculator: 24 34 = 0.7059 Convert from a decimal to a percentage: 0.7059 100 = 70.59 70.59 % Percentages Now do these:

1. 2. 3. 4. 5. 3 72 = 0.04167 0.04167 100 = 4.167 % 42 76 = 0.5526 Write 42 as a percentage of 76 0.5526 100 = 55.26 % 45 135 = 0.3333 Write 45 as a percentage of 135 0.3333 100 = 33.33 % 37 52 = 0.7115 Write 37 as a percentage of 52 0.7115 100 = 71.15 % 92 56 = 1.6429 Write 92 as a percentage of 56 1.6429 100 = 164.29 % Write 3 as a percentage of 72