Subtraction & Change

Overview

In this engaging 60-minute session, Year 3 students will consolidate their understanding of decimals and money through practical subtraction problems and realistic scenarios involving finding change. Following the National Curriculum for England (Mathematics programme of study, Year 3), the lesson will develop fluency in subtraction with decimals and place value, and apply these skills in solving everyday problems related to money.

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National Curriculum Links

Mathematics – Year 3

• Number - Fractions: Recognise and use fractions as numbers (including decimals).
• Number - Addition and Subtraction: Add and subtract numbers with up to three digits, using formal written methods of columnar addition and subtraction where appropriate.
• Measurement – Money: Add and subtract amounts of money to give change, using both £ and p in practical contexts.

Key Learning Objectives
By the end of the lesson, all pupils will be able to:

• Subtract amounts of money including decimals to the nearest penny.
• Calculate change accurately in a context of buying and selling.
• Apply arithmetic strategies confidently in practical money situations.

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Lesson Breakdown

1. Starter: Recap and Mental Warm-up (10 minutes)

• Activity: Quick mental subtraction quiz on decimally expressed money amounts (e.g., £2.50 - £1.75). Write answers on mini whiteboards.
• Purpose: Refresh subtraction skills with decimals and reinforce place value knowledge.
• Support: Use number lines for those struggling to conceptualise subtraction with decimals.

2. Introduction: Understanding Change (10 minutes)

• Teacher Explanation:
  • Explain how to subtract the cost of an item from the amount given to find change, using a clear example on the board (e.g., Customer pays £5 for something costing £3.60, how much change?).
  • Emphasise decimal notation (pounds and pence) and place value (ones, tenths, hundredths).
• Class Discussion:
  • Explore common mistakes (“Can you give more change than you paid?”).
  • Reinforce the importance of lining up decimal points.

3. Main Activity: Mock Shop Role-Play (25 minutes)

• Setup:

  • Arrange a “shop” with 10 items labelled with prices (all under £10, with decimals, e.g., £1.50, £3.75).
  • Children split into pairs or small groups, alternating between shopkeepers and customers.
  • Each customer is given a selection of different notes and coins (£5, £1, 50p, etc.) and a shopping list with items to purchase.

• Task:

  • Customers select 2-3 items, calculate total cost (by adding prices already taught in previous lessons).
  • Pay with a given amount (e.g., £10 note) and calculate change using subtraction.
  • Shopkeepers check answers and role-play giving change correctly.

• Resources:

  • Play money, price tags, shopping lists, paper and pencils for calculations.

4. Plenary and Assessment (15 minutes)

• Group Reflection: Discuss challenges faced and strategies used to find change quickly.

• Evidence of Learning:

  • Each pair records one example calculation of total cost, payment, and change given on a worksheet.
  • Teacher collects worksheets to assess accuracy and procedural understanding.

• Class Challenge: “If you get £5.00 and buy something for £2.65, how much change do you receive?”—call on pupils randomly to answer to reinforce quick mental recall.

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Differentiation

• SEN Support: Provide scaffolded number lines and visual aids. One-to-one adult support during mock shop activity. Pre-printed calculation templates with step-by-step subtraction.
• Greater Depth: Challenge pupils to explain their reasoning orally, including place value concepts; estimate change before calculating; try combinations of prices to stay under a certain amount.

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Assessment for Learning

• Observation during role-play: accuracy, confidence, and communication.
• Worksheets checked for correct calculation and understanding of place value.
• Questioning throughout to probe understanding and clear misconceptions immediately.

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Resources Needed

• Printed price labels and shopping lists with decimal prices.
• Play money (notes and coins).
• Mini whiteboards and pens.
• Worksheets for recording calculations.
• Number lines for decimal numbers.

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Extensions & Home Learning

• Extension: Design your own shop catalogue with new decimal prices and invite family to “shop” with you, practising change at home.
• Home Task: Identify items at home/shop with prices including decimals; practise calculating change from given amounts.

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This lesson plan combines National Curriculum rigour with active learning through role play, fostering both confidence and skills in money management and decimal subtraction. By embedding knowledge in a real-life context, it greatly enhances understanding and retention among Year 3 pupils.