Mathematics · 1st Class · Money · Summer Term

Calculating Simple Change

What happens when you pay with more money than you need? We will learn how to work out how much change you should get back from the shopkeeper.

TL;DR:Ready to turn your classroom into a bustling marketplace? This topic helps pupils apply their number skills to a real-world scenario they all understand: buying things at the shop.

• NCCA Curriculum Specifications
• PSMC: Measures - Money

About This Topic

This topic, Calculating Simple Change, is a fundamental component of the Measures strand in the Irish Primary School Mathematics Curriculum (PSMC), specifically within the Money substrand for First Class. Building upon the infant classes' work of recognising and using coins up to 5c and 10c, this topic introduces the concept of transactions and the resulting change. It provides a practical, real-world context for applying early subtraction and addition skills, moving children from concrete manipulation of coins to more abstract problem-solving.

The core pedagogical approach should be hands-on and exploratory, using play money and role-play scenarios to mimic real-life shopping experiences. The focus is on developing a conceptual understanding of change, not just rote memorisation of subtraction facts. By engaging with problems like finding change from 10c and 20c, pupils develop number sense, mental maths strategies (such as 'counting up'), and an appreciation for the practical application of mathematics in their daily lives. This topic lays the groundwork for more complex financial literacy concepts they will encounter in later classes.

Key Questions

1. Identify the change you get from 10c if you buy a sweet for 8c.
2. Explain how to calculate your change from 20c for an item costing 15c.
3. Compare the change you get from 10c for a 6c item versus a 4c item.

Learning Objectives

• Calculate change from 10c for items of varying cost.
• Calculate change from 20c using subtraction or a 'counting up' strategy.
• Solve one-step word problems involving simple purchases and change.
• Demonstrate the process of giving change using play money in a role-play scenario.
• Compare the amount of change received from different transactions.

Key Vocabulary

Change	The money you get back when you pay for something with more money than it costs.
Cost	The amount of money you need to pay to buy something. Also called the price.
Cent	A coin used in Ireland. 100 cent make one Euro.
Spend	To use money to pay for something.
Left over	The amount remaining after a part has been taken away. Your change is the money left over.

Watch Out for These Misconceptions

Common Misconception

Pupils add the cost of the item to the money they have, instead of subtracting.

What to Teach Instead

Explain that when you buy something, the shopkeeper keeps the cost. The change is the money 'left over'. Use physical coins to demonstrate the removal of the cost from the initial amount.

Common Misconception

The calculation is correct, but the pupil uses the wrong coins to represent the change (e.g., gives two 2c coins for 3c change).

What to Teach Instead

Reinforce coin values regularly. Have pupils practise counting out specific amounts using different combinations of coins before tackling the concept of change.

Common Misconception

Pupils struggle with the abstract subtraction and guess the answer.

What to Teach Instead

Always link the problem back to a concrete method. Encourage 'counting up' from the price to the amount paid using a number line or by physically handling coins.

Active Learning Ideas

Practical Life Work

Classroom Shop

Set up a small shop in the classroom with priced items (e.g., pencils, rubbers, small toys) all under 20c. Pupils take turns being the customer and the shopkeeper, using play money to buy items and calculate the correct change.

30 min·Pairs

Practical Life Work

Change Grids

Provide pupils with a simple grid. One column shows an item's price (e.g., 8c, 12c, 5c), and the next column shows 'Paid with' (e.g., 10c, 20c). Pupils must work out the change and write it in the final column.

15 min·Individual

Practical Life Work

Counting Up Challenge

Give pupils a starting number (the price) and a target number (the money paid). They must use 1c and 2c coins to physically 'count up' from the price to the target, and then count the coins they used to find the change.

20 min·Small Groups

Real-World Connections

• Buying a copybook or pencil in the local newsagent.
• Getting a small treat like a chocolate bar or a bag of crisps from the shop.
• Paying for a ride on a carousel at a funfair.
• Putting money in a charity collection box.
• Using pocket money to buy a comic or a small toy.

Assessment Ideas

Quick Check

Observe pupils during the 'Classroom Shop' activity. Note their strategies for calculating change, their accuracy, and their ability to explain their thinking.

Quick Check

Provide a short worksheet with 3-4 illustrated problems, such as: 'A banana costs 15c. You pay with a 20c coin. Draw the change you get back'.

Quick Check

After a lesson, ask pupils to hold up a red (I need help), yellow (I'm not sure), or green (I understand) card to indicate their confidence level.

Frequently Asked Questions

What is the best strategy to teach first: subtraction or 'counting up'?

For this age group, the 'counting up' method is often more intuitive and concrete. It builds on addition skills they are already familiar with and physically demonstrates the 'difference' between the two amounts.

My pupils are struggling to apply this to word problems. What can I do?

Start with extensive role-play so they understand the context. Then, break down word problems together as a class, identifying the key numbers: 'How much money do you have?' and 'How much does the item cost?'.

How can I differentiate for pupils who find this easy?

Challenge them to calculate change from 50c, buy two items and calculate the total cost before working out the change, or ask them to find all the possible coin combinations for a specific amount of change.