Unit prices for children
Compare cost per item to find better value.
Quick answer
Unit prices help you find the best deal when shopping by comparing how much each item costs. You can find the unit price by dividing the total cost by the number of items.
Learning outcome
By the end of this page, you will be able to compare unit prices to find the best value when buying things.
- You can calculate the cost of one item when given the total cost and number of items.
- You can compare two or more prices to find the cheapest option.
- You can use unit prices to make smart shopping decisions.
- You can explain why unit prices help you save money.
Why this matters
Unit prices are useful in everyday life when you are shopping. They help you decide which pack of sweets, which box of cereal, or which bag of apples gives you the best deal for your money. Understanding unit prices helps you become a smart shopper and save money for things you want!
When you grow up, you will use unit prices to compare prices for bigger things like groceries, clothes, and even car fuel. This skill will help you make better choices and be more confident with money.
How it works
Unit prices are found by dividing the total cost by the number of items. Here’s how:
- Find the total cost of a pack or bag of items.
- Count how many items are in that pack or bag.
- Divide the total cost by the number of items.
- Compare the unit prices to see which is the cheapest.
For example, if a pack of 6 eggs costs £1.20, the unit price is £1.20 ÷ 6 = £0.20 per egg.
Examples you can see
Let’s look at some examples to help you understand unit prices better.
Example 1: Buying Apples
Imagine you are shopping for apples. You see two bags:
- Bag A: 5 apples for £2.00
- Bag B: 10 apples for £3.50
Let’s work out the unit price for each:
| Bag | Total Cost | Number of Apples | Unit Price |
|---|---|---|---|
| Bag A | £2.00 | 5 | £2.00 ÷ 5 = £0.40 |
| Bag B | £3.50 | 10 | £3.50 ÷ 10 = £0.35 |
Bag B costs less per apple, so it’s the better value!
Example 2: Buying Chocolate
You are looking at two chocolate bars:
- Bar X: 3 bars for £3.00
- Bar Y: 6 bars for £5.40
| Bar | Total Cost | Number of Bars | Unit Price |
|---|---|---|---|
| Bar X | £3.00 | 3 | £3.00 ÷ 3 = £1.00 |
| Bar Y | £5.40 | 6 | £5.40 ÷ 6 = £0.90 |
Bar Y is cheaper per bar, so it’s the better choice.
Example 3: Buying Juice
You are buying juice boxes:
- Box 1: 4 juice boxes for £2.40
- Box 2: 8 juice boxes for £4.00
| Box | Total Cost | Number of Boxes | Unit Price |
|---|---|---|---|
| Box 1 | £2.40 | 4 | £2.40 ÷ 4 = £0.60 |
| Box 2 | £4.00 | 8 | £4.00 ÷ 8 = £0.50 |
Box 2 is the better value because it costs less per juice box.
Try it as a mini adventure
Mini Adventure: The Supermarket Shopping Challenge
You are going to the supermarket with your parent or carer. You are given £10 to spend and must buy the best value items. You must pick 3 different items and calculate their unit prices.
Here’s your challenge:
- Find a pack of 6 yoghurts for £2.40.
- Find a pack of 12 biscuits for £3.60.
- Find a pack of 4 oranges for £1.60.
Work out the unit price for each item and decide which is the best value. Then, use your £10 to buy the items you think are best value. How much money do you have left?
How to do it:
- Yoghurt: £2.40 ÷ 6 = £0.40 each
- Biscuit: £3.60 ÷ 12 = £0.30 each
- Orange: £1.60 ÷ 4 = £0.40 each
The biscuits are the best value! You can buy 12 biscuits for £3.60 and save money compared to the others.
Common mistakes
- Mistake: Thinking that the bigger pack is always better value.
- Why it happens: Children often think that if you buy more, you save more money. But this isn’t always true if the unit price is higher.
- Fix: Always calculate the unit price to compare properly.
- Mistake: Not dividing the total cost by the number of items.
- Why it happens: Children might add the costs or count items incorrectly.
- Fix: Use a calculator or write out the division clearly.
- Mistake: Comparing prices without calculating the unit price.
- Why it happens: It’s easy to see which total is cheaper but not which is cheaper per item.
- Fix: Always divide the total cost by the number of items to find the unit price.
Parent and carer guide
As a parent or carer, you can help your child learn about unit prices by:
- Shopping together and asking them to calculate unit prices for different items.
- Using real-life examples like buying fruit, sweets, or drinks.
- Encouraging them to use a calculator or write out the division to check their work.
- Practising with different scenarios to build confidence.
- Noticing when they make mistakes and gently correcting them with clear examples.
Remember, this is a new skill, so be patient. Your child may need time to understand how to compare unit prices, but with practice, they will get better.
Practice questions
- Question: A pack of 5 pencils costs £1.50. What is the unit price?
- Answer: £1.50 ÷ 5 = £0.30
- Question: A bag of 10 marbles costs £2.00. What is the unit price?
- Answer: £2.00 ÷ 10 = £0.20
- Question: A box of 4 crayons costs £1.20. What is the unit price?
- Answer: £1.20 ÷ 4 = £0.30
- Question: A pack of 8 stickers costs £2.40. What is the unit price?
- Answer: £2.40 ÷ 8 = £0.30
- Question: A pack of 12 cookies costs £3.60. What is the unit price?
- Answer: £3.60 ÷ 12 = £0.30
FAQ
What is a unit price?
A unit price is how much one item costs. It helps you compare prices between different packs or bags.
Why do we need unit prices?
Unit prices help you save money by finding the best deal. You can buy more for less when you compare unit prices.
How do I calculate unit price?
You divide the total cost by the number of items. For example, if 5 apples cost £2.50, the unit price is £2.50 ÷ 5 = £0.50 per apple.
Can I use unit prices for anything else?
Yes! You can use unit prices for anything you buy, like drinks, snacks, clothes, or even fuel for a car.
How can I practice unit prices at home?
You can practice by looking at prices in the supermarket or online and calculating how much each item costs. You can also use items from your home like toys, books, or snacks to make up your own problems.