Need help with Level 5-6 Numbers - Percentages - Increases and Decreases? Ask our AI Tutor!

AI Tutor - Lucy

Connecting with Tutor...

Please wait while we establish connection

Hi! I'm Lucy, your AI tutor. How can I help you with Level 5-6 Numbers - Percentages - Increases and Decreases today?

now

Maths Quiz - Level 5-6 Numbers - Percentages - Increases and Decreases (Questions)

Percentages help track change. Learn how increases and decreases work, and why repeated percentage changes use multiplication, not simple addition.

Explore the Topic →

(quiz starts below)

Fascinating Fact:

Compound changes multiply repeatedly, two 10 percent rises are not 20 percent total, but 1.10 × 1.10 = 1.21, a 21 percent increase.

In KS3 Maths, you study percentage increases and decreases to model real price changes, discounts, and growth. Using multipliers (like 1.2 or 0.85) keeps calculations fast and accurate.

Key Terms

Percentage: A fraction out of 100, written with the percent symbol (%).
Multiplier: The number you multiply by to apply a percentage change, for example 1.08 for an 8% increase.
Compound change: Repeated percentage change where each step builds on the last using multiplication.

Frequently Asked Questions (Click to see answers)

How do you increase a number by a percentage in KS3?

Convert the percentage to a multiplier and multiply. For example, increase 250 by 12% using 250 × 1.12 = 280.

How do you decrease a number by a percentage?

Use a multiplier less than 1. A 15% decrease uses 0.85. Example: 60 × 0.85 = 51.

Why are two 10% increases not equal to a single 20% increase?

Because the second 10% is on the new value. 1.10 × 1.10 = 1.21, which is a 21% total increase, not 20%.

Try These Related Quizzes

1.

In a sale, all the prices are reduced by 20%. Find the sale price of a washing machine which originally cost £299.

[ ]	£60
[ ]	£100
[ ]	£176.30
[ ]	£239.20

2.

Bob, the local car dealer, is reducing all his cars by 15%. Find the reduced price of a Nissan which originally cost £690.

[ ]	£580.60
[ ]	£585.50
[ ]	£586.50
[ ]	£590.90

3.

A train's top speed is 140 mph. After a service, its top speed increases by 12%. What is the new top speed?

[ ]	150 mph
[ ]	156 mph
[ ]	156.4 mph
[ ]	156.8 mph

4.

To find the result of increasing a number by 13% you multiply it by .......

[ ]	1.13
[ ]	1.3
[ ]	1.31
[ ]	87

5.

To find the result of decreasing a number by 7% you multiply it by .......

[ ]	0.9
[ ]	0.93
[ ]	1.07
[ ]	1.7

6.

Thomas earns £22,500 per year. He receives a pay rise of 4.4%. How much does he now earn?

[ ]	£23,000
[ ]	£23,400
[ ]	£23,450
[ ]	£23,490

7.

Simon bought his computer for £230. A year later he sold it for 20% less than he paid for it. How much was it sold for?

[ ]	£164
[ ]	£184
[ ]	£204
[ ]	£224

8.

To find the result of increasing a number by 66% you multiply it by .......

[ ]	1.16
[ ]	1.6
[ ]	1.66
[ ]	34

9.

Harold owns a 14% stake in a company worth £250,000. How much is Harold's stake worth?

[ ]	£35,000
[ ]	£40,000
[ ]	£45,000
[ ]	£50,000

10.

The local football team are playing badly and the number of season tickets sold reduces by 17% from last year. If 3,700 tickets were sold last year, how many were sold this year?

[ ]	3,000
[ ]	3,071
[ ]	3,091
[ ]	3,099

You can find more about this topic by visiting BBC Bitesize - Percentages

Maths Quiz - Level 5-6 Numbers - Percentages - Increases and Decreases (Answers)

1.

In a sale, all the prices are reduced by 20%. Find the sale price of a washing machine which originally cost £299.

[ ]	£60
[ ]	£100
[ ]	£176.30
[x]	£239.20

One way is 20 / 100 x £299 = £59.80. Then subtract £59.80 from £299 to get £239.20

2.

Bob, the local car dealer, is reducing all his cars by 15%. Find the reduced price of a Nissan which originally cost £690.

[ ]	£580.60
[ ]	£585.50
[x]	£586.50
[ ]	£590.90

Another way is to use a multiplier. A 15% decrease is a mutliplier of 100 - 15 = 85%. 85% = 0.85 (just divide 85 by 100). £690 x 0.85 = £586.50

3.

A train's top speed is 140 mph. After a service, its top speed increases by 12%. What is the new top speed?

[ ]	150 mph
[ ]	156 mph
[ ]	156.4 mph
[x]	156.8 mph

A 12% increase is a multiplier of 1.12. 1.12 x 140 = 156.8

4.

To find the result of increasing a number by 13% you multiply it by .......

[x]	1.13
[ ]	1.3
[ ]	1.31
[ ]	87

If something is increased by x% then its original value will have to be multiplied by (1 + x) to find the new value. The 1 represents 100% and the x represents the percentage increase: in this case (1 + x) = (1 + 0.13) = 1.13. If there was a decrease of x%, then you would have to multiply the original value by (1 - x)

5.

To find the result of decreasing a number by 7% you multiply it by .......

[ ]	0.9
[x]	0.93
[ ]	1.07
[ ]	1.7

Percentages are easily converted to decimals. Just divide by 100 (or move digits)

6.

Thomas earns £22,500 per year. He receives a pay rise of 4.4%. How much does he now earn?

[ ]	£23,000
[ ]	£23,400
[ ]	£23,450
[x]	£23,490

4.4% of 22,500 is 990. To work this out you could multiply 22,500 x 0.044 (4.4 hundredths)

7.

Simon bought his computer for £230. A year later he sold it for 20% less than he paid for it. How much was it sold for?

[ ]	£164
[x]	£184
[ ]	£204
[ ]	£224

To work out 20% just divide by 5

8.

To find the result of increasing a number by 66% you multiply it by .......

[ ]	1.16
[ ]	1.6
[x]	1.66
[ ]	34

Calculations are much easier if a multiplier is used

9.

Harold owns a 14% stake in a company worth £250,000. How much is Harold's stake worth?

[x]	£35,000
[ ]	£40,000
[ ]	£45,000
[ ]	£50,000

To find 14% multiply by 0.14

10.

The local football team are playing badly and the number of season tickets sold reduces by 17% from last year. If 3,700 tickets were sold last year, how many were sold this year?

[ ]	3,000
[x]	3,071
[ ]	3,091
[ ]	3,099

To find 17% multiply by 0.17