Understanding percentages Functional Maths Understanding percentages

Let’s talk about percentages Work in a small group. Talk about what you know about percentages. When do we see percentages in everyday life? When do you use percentages at work? What is a percentage? Why do we use percentages?

What is a percentage? 1 100 The word ‘percentage’ comes from the Latin Per = for, out of (£10 per hour) Cent = 100 (100 cents in 1$, 100 years in a century) 1 100 Out of

can be shown like this… 1 100 Divide the whole into 100 parts Take 1 part = 1%

What does 1% look like? 1% = 1 100

What does 10% look like? 10% = 10 = 1 100 10

What does 20% look like? 20% = 20 = 2 = 1 100 10 5

What does 25% look like? 25% = 25 = 1 100 4

What does 50% look like? 50% = 50 = 1 100 2

What does 25% look like? 25% = 25 = 1 100 4

What does 25% look like? 25% = 25 = 1 100 4

What does 25% look like? 25% = 25 = 1 100 4

What does 47% look like? 47% = 47 100 Try to visualise trickier percentages 47% = nearly a half

Finding a percentage of - a quantity - an amount

1% = 1 = divide by 100 100 Divided by What is 1% of 200?

5% = 5 = divide by 100 then times by 5 100 What is 5% of 200? What is 5% of 300? What is 5% of 500? What is 5% of 4000? What is 5% of 3476? What is 5% of 24.50?

5% = 5 = divide by 100 then times by 5 100 What is 5% of 200? What is 5% of 300? What is 5% of 500? What is 5% of 4000? What is 5% of 3476? What is 5% of 24.50? Without a calculator 5 = 1 100 = 20 So you could divide by 20. Divide by 10 Take half the answer

What is 5% of 450?

Three routes, one destination 450 x 5 100 ÷ by 5 x 450 100 22.5 ÷ by 450 x 5 100 ÷ by

450 ÷ 100 x 5 450 divided by 100 (for 1%) . = 4.5 Multipied by = 22.5 OR You can do 5 ÷ 100 x 450 5 divided by 100 = 0.05 Multiplied by 450 = 22.5 OR You can do 450 x 5 ÷ 100 450 multiplied by 5 = 2250 Divided by 100= 22.5

On a calculator you can use the % button. What is 5% of 450? 450 x 5 100 450 x 5 ÷ 100 On a calculator you can use the % button. 450 x 5%

On a calculator you can use the % button. What is 5% of 450? 450 x 5 100 450 x 5 ÷ 100 On a calculator you can use the % button. 450 x 5% The % button divides a number by 100

Word problems You pay £550 per month rent. Your landlord decides to increase your rent by 5%. How much more rent do you have to pay per month? A research company asked 12,000 local residents over 65 about their heating bills. 78% of respondents said that they were worried about the cost of heating. How many people is that? Knitwear is on offer in the end of season sale. There is 30% off the ticket price. You buy a jumper with a ticket price of £30. How much do you pay for the jumper?

Questions about percentages A percentage of an amount One number as a percentage of another

A percentage of an amount 16 out of the 20 students in a maths class are single. Make the fraction 16 20 Out of

16 out of the 20 students in a maths class are single. A fraction of an amount 16 out of the 20 students in a maths class are single. Make the fraction Divide top by bottom = 0.8 16 20 Out of

A percentage of an amount 16 out of the 20 students in a maths class are single. Make the fraction Divide top by bottom = 0.8 Multiply by 100 = 80% 16 20 Out of

A percentage of an amount 16 out of the 20 students in a maths class are single. What % are married? 80% are single All students = 100% 100% - 80% are single = 20%

A percentage of an amount 478 of the 1400 people interviewed in a survey about healthy eating said they never eat vegetables? What percentage is that?

A percentage of an amount 9 children in a primary school class of 23 children are boys. What percentage are boys? What percentage are girls?

Word problems An FE college has been looking at its enrolment figures and found out that 1400 of the 3,500 students are female. A) What % is female? B) What % is male? In a survey of student satisfaction, 1250 if the 1750 people asked said that they were happy with the course. A) What % is happy? B) What % is mot happy?

What % of income does each represent?

1% 1 0.01 100

25% 25 = 0.25 100