Simplifying Fractions Mastery

Overview

This 55-minute lesson is designed for Year 6 students (ages 10-11) to build on their prior knowledge of equivalent fractions by deepening their understanding of when fractions are and are not in their simplest form. Through hands-on and visual activities using fraction walls and bar models, pupils will identify common factors to simplify fractions effectively. This lesson fully aligns with the National Curriculum for England Mathematics Programme of Study for Key Stage 2.

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National Curriculum Links

• Number - Fractions (Yr 6):
  • Use common factors to simplify fractions; use common multiples to express fractions in the same denomination.
• Mathematical fluency and reasoning: pupils apply understanding of factors to manipulate and simplify fractions, enhancing procedural and conceptual fluency.

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Learning Objectives

By the end of this lesson, pupils will:

1. Identify common factors of numerators and denominators confidently to simplify fractions.
2. Recognise fractions in simplest form by understanding when numerator and denominator share no common factors above 1.
3. Use visual fraction models (fraction walls and bar models) to compare equivalent fractions and support simplification.
4. Explain simplification steps verbally and in writing, demonstrating understanding that simplification may take one or multiple steps.

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Success Criteria

• I can find all common factors of two numbers.
• I can simplify fractions by dividing numerator and denominator by their greatest common factor (GCF).
• I can say why a fraction is or isn’t in its simplest form.
• I can use fraction walls or bar models to show equivalent fractions visually.
• I can explain the process of simplifying a fraction in more than one step if needed.

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Resources

• Printed fraction walls for each pupil or displayed on interactive whiteboard
• A collection of fraction bars (sets of coloured strips representing fractions)
• Whiteboards & pens for group work
• Worksheets with starter questions and simplification exercises
• Mini dry wipe boards and markers for each pupil
• Visual aid poster displaying common factors and greatest common factor (GCF) method
• Laptops/tablets (if available) with fraction visualisation apps (optional)

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Lesson Structure

1. Starter (10 minutes) — Revise Common Factors & Spot Equivalent Fractions

• Activity:
  • On whiteboards, pupils list factors of pairs of numbers (e.g., 15 and 25); identify common factors together.
  • Use fraction bars to compare pairs such as 3/5 and 6/10 displayed visually.
• Key Question:
  • Are these two fractions equal? How can we verify?
  • Which fraction is simpler and why?
• Purpose: Activate prior knowledge, connect factors to equivalent fractions before simplification.

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2. Introduction & Teacher Modelling (10 minutes)

• Teacher demonstrates how to find the greatest common factor (GCF) of numerator and denominator.
• Show step-by-step simplification example: 18/24 simplified by dividing by 6 (GCF) to get 3/4.
• Use fraction wall to show this equivalence visually.
• Discuss concept that sometimes simplification happens in multiple steps (e.g., 12/20 ÷ 2 = 6/10 ÷ 2 = 3/5).

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3. Main Activity (25 minutes) — Hands-On Simplifying Fractions

• Task 1 (15 minutes):

  • Pupils work in pairs with fraction bars or printed fraction walls. They pick fraction cards (e.g., 8/12, 15/25, 20/30) and:
    • Find common factors of numerator & denominator
    • Simplify the fraction stepwise or in one step
    • Use fraction bars to verify equivalent simplified fraction visually
  • Pupils record their work on mini whiteboards, showing factors found and simplification steps.

• Task 2 (10 minutes):

  • Each pair chooses one fraction to present simplification steps and visual proof to class with fraction bars or fraction wall on whiteboard.
  • Peers ask questions to encourage verbal explanation and reasoning.

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4. Plenary (10 minutes) — Reflect & Assess Understanding

• Teacher-led discussion addressing:
  • “How do you know a fraction cannot be simplified further?”
  • “Why is 3/5 simpler than 6/10?”
• Quick quiz on mini whiteboards: Teacher calls out fractions and pupils write if fraction is in simplest form or not, and if not, provide a simplified form.
• Summative question: "Explain the process you would use to simplify 24/32." (Orally and on mini boards)

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Differentiation

• Support:
  • Use fraction walls extensively for visual learners. Provide number factor charts and GCF reminders.
  • Pair less confident pupils with stronger partners.
  • Scaffold with guided questioning during tasks.
• Challenge:
  • Find multiple ways to simplify some fractions (e.g., dividing by smaller factors first).
  • Explain why fractions like 7/9 are already simplest.
  • Investigate fractions with larger denominators.

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Assessment Opportunities

• Observe paired work and listen to pupil explanations for verbal reasoning.
• Monitor mini whiteboard responses during starter, main tasks, and plenary to assess fluency.
• Evaluate pupils’ written simplification steps on worksheets or whiteboards.
• Use plenary quiz to assess grasp of simplest form concept.

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Classroom Organisation & Additional Tips

• Seating arranged in pairs for collaboration.
• Use an interactive fraction wall on whiteboard to demo throughout lesson.
• Incorporate mini whiteboard use to enable immediate formative assessment and feedback.
• Encourage use of mathematical language: factor, common factor, simplify, greatest common factor, equivalent fractions, simplest form.

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This lesson plan ensures pupils build deep conceptual understanding and procedural fluency in simplifying fractions, supported by visual aids and active participation — fulfilling the National Curriculum's emphasis on both understanding and fluency in mathematics.