Subtracting Fractions

Lesson Overview

• Unit: Fraction Fun Adventures (Lesson 6 of 9)
• Subject: Mathematics
• Year Group: Year 3
• Lesson Duration: 60 minutes
• Curriculum Area: National Curriculum for England (Year 3: Fractions)
• Learning Objective: By the end of this lesson, students will be able to subtract fractions with the same denominator confidently using visual models and numerical calculations.
• Key Vocabulary: Fraction, denominator, numerator, subtraction, equal parts

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Lesson Structure

1. Starter Activity (10 minutes) – Fraction Warm-Up

Objective: Revisit the concept of fractions with like denominators.

Activity:

• Use a Fraction Pizza cut into equal slices (e.g., a magnetic or printed fraction pizza).
• Ask the student to recall how to write fractions based on the number of slices present (e.g., 3/6).
• Ask: “If I eat 2 slices, how many are left?” Encourage them to think about subtracting fractions in a real-life context.
• Record the subtraction equation: 3/6 - 2/6 = 1/6

Questioning:

• "Why does the denominator stay the same?"
• "What happens to the numerator when we take slices away?"

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2. Direct Teaching (15 minutes) – Step-by-Step Explanation

1. Introduce the Rule – Explain that when subtracting fractions with the same denominator, we simply subtract the numerators while keeping the denominator the same.

   Example: 5/8 - 3/8 = (5 - 3)/8 = 2/8

2. Demonstrate With Visual Models – Use fraction bars or circles to show physically removing parts to reinforce understanding.

3. Write Sample Equations Together – Work through a few examples:

   • 4/7 - 1/7
   • 6/9 - 2/9
   • 7/10 - 4/10

4. Common Mistakes To Address:
   “Do I subtract the denominator?” ➝ No, we only subtract the numerators!

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3. Guided Practice (15 minutes) – Subtract & Colour

Activity: Fraction Colour Puzzles

• The student gets a worksheet with different fraction subtraction problems. Each answer has a corresponding colour.
• Once they solve a problem, they colour a section of a picture based on their answer.
• This actively engages them while reinforcing the concept.

Examples In Workbook:

• 5/6 - 2/6
• 9/12 - 4/12
• 7/9 - 3/9

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4. Independent Practice (10 minutes) – Challenge Questions

• Present word problems involving real-life scenarios:

  1. Lily baked a chocolate cake and cut it into 8 equal slices. She ate 3 slices. How many slices of cake are left? (Solve using fractions!)
  2. A jug has 5/7 litres of water. If 2/7 litres are poured out, how much is left?

• Encourage students to draw models alongside their answers.

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5. Plenary (10 minutes) – Fraction Showdown

Game: Quick-Fire Fraction Subtraction

• Ask subtraction fraction questions aloud.
• The student must give quick responses within 5 seconds!
• If they hesitate, encourage them to explain their thinking before revealing the correct answer.

Key Challenge: Can they create their own subtraction question for the teacher to answer?

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Assessment Opportunities

• Observation: Assess accuracy during guided practice.
• Student Response: Listen to reasoning in verbal discussions.
• Written Work: Mark independent work to check proper method and accuracy.

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Resources Needed

✔ Fraction circles/bars (printed or drawn)
✔ Whiteboard and markers
✔ Subtract & Colour worksheet
✔ Word problem sheet

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Differentiation Strategies

• Support: Use physical counters for those who struggle with numerical subtraction.
• Challenge: Introduce fraction simplification (e.g., 4/8 - 2/8 = 2/8, which simplifies to 1/4).
• Visual Learners: Use fraction diagrams throughout.

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Teacher Reflection

• What went well? (E.g., Did students grasp the concept of keeping the denominator the same?)
• What could be improved? (E.g., Were real-life examples engaging?)
• Next Steps: (Prepare for Lesson 7 – Equivalent Fractions!)

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💡 Teacher Tip: Use real food items (e.g., an actual pizza or chocolate bar) to make fractions feel more real-world before starting numerical practice.

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🎉 End of Lesson – Well Done! 🎉