SMART MATH · MATHS IN REAL LIFE
Why Can Your Money Buy Less Over Time? | Understanding Inflation
🎬 Inflation in Everyday Life
Imagine having £10 to spend at the supermarket. Over time, as prices rise, that same £10 may no longer buy everything it once did. This is the effect of inflation. Let's explore how percentages help us understand changes in prices and the purchasing power of money.
Watch this short video to see how inflation can affect the things we buy.
MathsWealth · Smart Maths. Real Wealth.
1. What Is Inflation?
Inflation is a general increase in the prices of goods and services over time.
When prices rise, the purchasing power of money falls. This means that the same amount of money may buy fewer goods and services than before.
💡 The Key Idea
If prices increase but your budget stays the same, you may have to buy less.
Inflation is not simply about one product becoming more expensive. It describes a broader rise in prices across the economy.
2. The Same Shopping Basket, a Different Price
Imagine buying the same three products at the supermarket in two different years.
| Item | Last Year | This Year |
|---|---|---|
| Milk | £1.00 | £1.10 |
| Bread | £1.20 | £1.50 |
| Eggs | £2.00 | £2.40 |
| Total | £4.20 | £5.00 |
Last year, the shopping basket cost £4.20. This year, it costs £5.00.
The difference is:
£5.00 − £4.20 = £0.80
The shopping basket costs 80p more.
But how do we compare this increase fairly? This is where GCSE Maths comes in.
3. Calculate the Percentage Increase
An increase of 80p might sound small. However, the percentage increase tells us how large the change is compared with the original price.
Percentage Increase Formula
Percentage Increase =
(Increase ÷ Original Value) × 100
Step 1: Find the increase.
£5.00 − £4.20 = £0.80
Step 2: Divide by the original price.
£0.80 ÷ £4.20
Step 3: Multiply by 100.
(£0.80 ÷ £4.20) × 100 ≈ 19.0%
✅ Final Answer
The total cost of this example shopping basket increased by approximately 19.0%.
Note: These are fictional prices used to demonstrate percentage change. This shopping basket calculation is not an official measure of inflation.
4. Why Does the Original Value Matter?
When calculating a percentage increase, we divide the increase by the original value — not the new value.
In our example, the increase is £0.80 and the original price is £4.20. Dividing £0.80 by £5.00 would give a different answer because £5.00 is the new price.
⚠️ GCSE Exam Tip
For percentage change, always compare the change with the original value.
5. Your Turn: A GCSE Maths Challenge
A family spends £80 on a weekly shopping basket. The cost of the same basket increases by 5%.
What is the new cost?
A. £82
B. £84
C. £85
D. £88
Reveal the answer and working
Step 1: Find 5% of £80.
£80 × 0.05 = £4
Step 2: Add the increase.
£80 + £4 = £84
Correct answer: B. £84
6. What Does This Mean for Your Money?
Inflation affects everyday spending, from food and transport to energy and other household expenses.
If prices rise faster than your income, your money may lose purchasing power. You might need to spend more to maintain the same standard of living.
Understanding percentages helps us compare price changes, plan a budget and make informed financial decisions.
This is one way GCSE Maths becomes useful beyond the classroom.
📚 Explore More with MathsWealth
From percentage change to money management, maths can help us understand the financial decisions we make every day.
Explore more GCSE Maths topics and discover how mathematical ideas connect to real life.
MathsWealth — Smart Maths. Real Wealth.
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