WEEK 2 — Percentages & Rate of Change

 

Welcome to Week 2 of your eight-week maths catch-up plan.
This week builds on what you learned last week and focuses on understanding percentages properly — especially increases, decreases, and simple rate-of-change ideas.
Each day has a clear focus, a short explanation, and practice questions to help build confidence step by step.

The video at the top of the page gives the full lesson.
Below you’ll find the mind map, the daily breakdown, practice exercises, and a short quiz.

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Mind Map – Week 2

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DAY 1 — The 10% Rule (Foundation)

Today focuses on the simplest and most powerful percentage tool:
Find 10% → build all other percentages from it.

What to understand

• 10% = divide by 10

• 20% = double 10%

• 5% = half of 10%

• 25% = quarter of the number

• 50% = half of the number

Practice

Find:

10% of 90
20% of 150
5% of 120
25% of 80
50% of 60

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DAY 2 — Percentage Increase

Today you’ll learn how to increase a number by a percentage in a simple, understandable way.

What to understand

A percentage increase means:

original number + the percentage piece added on

Use the 10% rule to find the size of the piece.

Practice

Increase:

40 by 10%
120 by 20%
80 by 5%
200 by 50%
75 by 25%

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DAY 3 — Percentage Decrease

Today is the opposite of yesterday — instead of adding a percentage, you take one away.

What to understand

A percentage decrease means:

original number − the percentage piece removed

Again, the 10% rule makes this easy.

Practice

Decrease:

50 by 10%
200 by 20%
120 by 5%
400 by 25%
160 by 50%

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DAY 4 — Simple Rate of Change

A gentle introduction to the idea of rate of change — nothing difficult, just clear and visual.

What to understand

Rate of change means:

how much a value goes up or down compared to where it started

Today, you’re only finding the amount of change — not the percentage.

Practice

A price goes from €50 to €55 — what is the change?
A number goes from 40 to 30 — what is the change?
A score goes from 20 to 25 — what is the change?
A price drops from €100 to €80 — what is the change?
A number increases from 12 to 15 — what is the change?

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DAY 5 — Mixed Practice (Revision)

This day brings everything together from earlier in the week.

Practice

Find:

5% of 200
25% of 160
10% of 300

Increase:

60 by 20%

Decrease:

300 by 10%

Change:

A value rises from 70 to 84 — what is the change?

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Weekly Quiz — Week 2

👉 INSERT QUIZ IFRAME HERE (Google Forms embed)
(Use: Send → Embed → Copy iframe → paste in HTML view.)

The quiz is short and helps you check what you’ve understood.
If you’re stuck, use the mind map or rewatch the video.