Percentage Increase and Decrease | DigiTransact Mastermind

What percentage increase & decrease means

You learn how to change an amount by a given percentage, either up or down. This helps you work out new prices, scores, marks, and other everyday values quickly and correctly.

What you will practise

Find the increase as a fraction of the original amount
Add the increase to get the new amount
Find the decrease as a fraction of the original amount
Subtract the decrease to get the final amount
Check answers using simple percentage calculations

Before you start

You should be comfortable with multiplying and dividing whole numbers. You should also know how to find a percentage of a number.

Not confident yet? Work through Fractions, decimals & percentages first.

Worked example

One question from this skill's own question bank, shown with its full working.

Question

Increase 50 by 10%. What is the result?

Answer: 55

Working: 10% of 50 is 5, so 50 + 5 = 55.

Common mistakes to avoid

Using the changed amount instead of the original amount to find the percentage
Adding when the question asks you to decrease the amount
Forgetting to turn the percentage into a fraction or decimal first
Leaving out the final addition or subtraction after finding the change

Curriculum and exam alignment

Ghana GES Basic 7 to 9 syllabusBECE

This topic normally appears in Junior High School number work on percentages. It supports common BECE-style questions that ask you to find a new amount after a percentage change.

Curriculum notes are a general guide to where this work normally sits. Always check the syllabus your school or examination body is currently using.