Percentage increase and decrease, non-calculator methods

Help KS3 and KS4 students master percentage increase and decrease using non-calculator methods with this comprehensive maths resource, featuring a PowerPoint presentation and practice worksheet designed to build confidence and exam skills.

What's included

• Step-by-step PowerPoint presentation with accompanying worksheet
• Progressive practice questions are integrated throughout to check understanding
• Extension-style questions with worked solutions to build topic confidence

Access the activities as a free PDF download, or subscribe to unlock the editable PowerPoint and worksheet versions.

What do students need to know about percentage increase and decrease?

GCSE students should be taught to calculate percentage increases and decreases without a calculator by chunking percentages into simple, manageable parts. The emphasis is on understanding that 100% represents the original amount, and that other percentages can be built from key benchmarks such as 10%, 5%, and 1%.

Students should first develop fluency in finding:

• 10% by dividing by 10
• 1% by dividing by 100

They can then combine these to construct other percentages. For example, 15% can be found as 10% plus 5%, where 5% is half of 10%.

For percentage increase, students calculate the required percentage of the original amount and add this value to the starting amount.
For example, increasing £80 by 10% involves finding 10% of 80 (which is 8) and adding it, giving £88.

For percentage decrease, students again find the percentage of the original amount, but subtract it from the starting value.
For example, decreasing £80 by 10% involves finding 10% of 80 (which is 8) and subtracting it, giving £72.

Alongside these methods, students should also be introduced to decimal multipliers (e.g. multiplying by 1.15 for a 15% increase or 0.85 for a 15% decrease) and to reverse percentage calculations, ensuring they understand how these connect to the concept of the original 100%.

This percentages resource covers:

• percentage increase and decrease using non-calculator methods
• Activities to find a percentage
• Percentage increase
• Percentage decrease
• Extension questions

Percentage increase and decrease in GCSE maths

This resource supports the GCSE mathematics curriculum across all major exam boards (AQA, Edexcel and OCR). Students will develop skills in:

• Recognising and applying percentage increase or decrease to solve problems
• Finding percentages using established approaches
• Working with non-calculator methods
• Extending knowledge through extension activities

How to use this resource

Perfect for both classroom teaching and independent study, this resource can be used to introduce percentage increase and decrease using non-calculator methods or as a comprehensive revision tool. The PowerPoint follows a logical progression, allowing teachers to pause for discussion and worked examples, while the accompanying worksheet provides structured practice opportunities.

Looking for more like this?

Enhance your percentages teaching with these related resources:

• Percentage increase and decrease test
• Percentages booklet
• Percentages recap

For more percentages resources, visit our complete percentages collection