MathsPercentages and data25 min★★ difficulty

Percentage increase and decrease

Percentage change compares the change to the original amount — not to the new one. Multipliers make it fast and reversible.

Part of your national curriculum

Number: Work interchangeably with terminating decimals and their corresponding fractions, and define percentage as 'number of parts per hundred'
Ratio, proportion and rates of change: Solve problems involving percentage change, including percentage increase and decrease and original value problems
Statistics: Describe, interpret and compare observed distributions of a single variable through appropriate measures of central tendency and spread
Financial capability: Understand the functions and uses of money, the importance and practice of budgeting, and managing risk
Financial capability: Understand income, spending, saving and the choices involved in managing personal finances

Lesson overview

What you'll learn in this lesson

Calculate percentage increase and decrease

Key learning points

• Using multipliers
• Percentage change formula

This lesson at a glance

25 minutes
15 parts to scroll through
3 quick checks
Marked quiz at the end
Gentle pace: short sittings with pauses

Words to know

calculatepercentageincreasedecreasemultipliers

Scroll down — the lesson carries on below

Part 1 of 15 · Discover7%

Watch & discover

Part 1 of 15

Percentage increase and decrease illustration

Visual introduction

Picture this

Percentage increase and decrease

Percentage change compares the change to the original amount — not to the new one. Multipliers make it fast and reversible.

In a nutshell

Calculate percentage increase and decrease

Explore the idea

Part 2 of 15

Learn

Using multipliers

A 12% increase is × 1.12. A 12% decrease is × 0.88. Chain multipliers to apply several changes in a row.

Explore the idea

Part 3 of 15

Learn

Percentage change formula

change ÷ original × 100. Watch the sign: a fall is a negative change, usually reported as a percentage decrease.

Reset break

Part 4 of 15

Pause

That's sitting 1 of 4 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now

Explore the idea

Part 5 of 15

Worked example

Worked example — a population count

A monitored population falls from 480 to 372. Change = 108. 108 ÷ 480 × 100 = 22.5% decrease.

Quick check

Part 6 of 15

Quick check

Increase 240 by 15%.

Give me a hint

Quick check

Part 7 of 15

Quick check

A count drops from 200 to 150. The percentage decrease is…

Give me a hint

Reset break

Part 8 of 15

Pause

That's sitting 2 of 4 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now

Quick check

Part 9 of 15

Quick check

Which multiplier applies a 7% decrease?

Give me a hint

Challenge round

Part 10 of 15

Game · Sort it

Which of these are true?

Drag each card into the right column. Tap a card first if dragging is fiddly.

True

Not true

Challenge round

Part 11 of 15

Game · Fill the gaps

Finish the sentences

Choose the word that belongs in each gap.

A 12% ____ is × 1.12.

A 12% ____ is × 0.88.

Chain ____ to apply several changes in a row.

Reset break

Part 12 of 15

Pause

That's sitting 3 of 4 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now

Challenge round

Part 13 of 15

Game · Recall cards

Increase 240 by 15%.

Card 1 of 4

Mastery quiz

Part 14 of 15

Marked quiz

End of lesson quiz: Percentage increase and decrease

4 questions, marked with the reasoning shown. No timer.

1. Increase 240 by 15%.
2. A count drops from 200 to 150. The percentage decrease is…
3. Which multiplier applies a 7% decrease?
4. Write 3/8 as a percentage.

Lesson round-up

Part 15 of 15

Lesson round-up

Ready when you are

Quiz score

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Part 1 of 15 · Watch & discover

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How this is going

Not looked at yet
Work interchangeably with terminating decimals and their corresponding fractions, and define percentage as 'number of parts per hundred'
Not looked at yet
Solve problems involving percentage change, including percentage increase and decrease and original value problems
Not looked at yet
Describe, interpret and compare observed distributions of a single variable through appropriate measures of central tendency and spread
Not looked at yet
Understand the functions and uses of money, the importance and practice of budgeting, and managing risk
Not looked at yet
Understand income, spending, saving and the choices involved in managing personal finances