Fractions

Grade 4 · Mathematics

Semester 1 | Period 3 | Week 17

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Subject: Mathematics

Semester: 1

Period: 3

Week: 17

School Name:
Teacher’s Name:
Subject: Mathematics
Grade Level: Grade 4
Date: Week 17
Lesson Duration: 45 minutes
Week & Period: Week 17, Period 3
Topic: Fractions
Sub-topic: Adding and Subtracting Fractions; Solving Multi-step Problems

Learning Objectives
By the end of the lesson, students should be able to:

  1. Add and subtract fractions with like denominators.
  2. Add and subtract fractions with unlike denominators.
  3. Solve multi-step word problems involving fractions.

Previous Knowledge
Students already know how to find equivalent fractions and simplify them.

Instructional Materials
Mathematics textbook for Grade 4, fraction strips, fraction charts.

Lesson Development – ABC Model

A – Anticipation (Warm-up / Starter)
Time: 5–10 minutes
Teacher asks: “If you ate 1/4 of a cake in the morning and another 2/4 in the evening, how much did you eat in total?”

B – Building Knowledge (Main Lesson Body)
Time: 25–30 minutes

Addition with Like Denominators:
When fractions have the same denominator (bottom number), add the numerators (top numbers) directly and keep the denominator unchanged.
Example:
2/7 + 3/7 = (2 + 3)/7 = 5/7
5/9 + 1/9 = (5 + 1)/9 = 6/9 = 2/3 (simplified)

Subtraction with Like Denominators:
When fractions have the same denominator, subtract the numerators and keep the denominator.
Example:
5/9 – 2/9 = (5 – 2)/9 = 3/9 = 1/3 (simplified)
7/8 – 3/8 = (7 – 3)/8 = 4/8 = 1/2

Addition with Unlike Denominators:
Step 1: Find the Least Common Multiple (LCM) of the denominators.
Step 2: Convert each fraction to an equivalent fraction with the LCM as denominator.
Step 3: Add the numerators.
Step 4: Simplify if possible.
Example:
1/3 + 1/4
LCM of 3 and 4 is 12
Convert: 1/3 = 4/12, 1/4 = 3/12
Add: 4/12 + 3/12 = 7/12 (cannot simplify further)

Example:
2/5 + 1/10
LCM of 5 and 10 is 10
Convert: 2/5 = 4/10, 1/10 = 1/10
Add: 4/10 + 1/10 = 5/10 = 1/2 (simplified)

Subtraction with Unlike Denominators:
Follow the same steps as addition but subtract the numerators.
Example:
5/6 – 1/4
LCM of 6 and 4 is 12
Convert: 5/6 = 10/12, 1/4 = 3/12
Subtract: 10/12 – 3/12 = 7/12

Example:
3/4 – 1/6
LCM of 4 and 6 is 12
Convert: 3/4 = 9/12, 1/6 = 2/12
Subtract: 9/12 – 2/12 = 7/12

Multi-step Problem Example:
Mary ate 1/3 of an orange. Later she ate another 1/6. How much did she eat in total?
Step 1: Find LCM of denominators 3 and 6 → 6
Step 2: Convert fractions: 1/3 = 2/6, 1/6 = 1/6
Step 3: Add numerators: 2/6 + 1/6 = 3/6
Step 4: Simplify: 3/6 = 1/2
Mary ate half of the orange in total.

More Examples:

  1. Add 3/8 + 1/8 = (3 + 1)/8 = 4/8 = 1/2
  2. Subtract 7/10 – 2/10 = (7 – 2)/10 = 5/10 = 1/2
  3. Add 5/12 + 1/3
    LCM of 12 and 3 is 12
    5/12 + 4/12 = 9/12 = 3/4
  4. Subtract 11/15 – 2/5
    LCM of 15 and 5 is 15
    11/15 – 6/15 = 5/15 = 1/3

Learners’ Activities (Expanded):

  • Use fraction strips or bars to visually add and subtract fractions with like and unlike denominators.
  • Group work: Solve problems such as:
    • 2/5 + 1/5
    • 3/4 – 1/4
    • 2/3 + 1/6
    • 5/8 – 1/3 (find LCM first)
  • Word problem creation: Students write their own real-life fraction addition or subtraction problems (e.g., cooking recipes, sharing snacks).
  • Use number lines to demonstrate fraction addition and subtraction.

Assessment Checks:

  • What is 4/12 + 2/12? (Answer: 6/12 = 1/2)
  • Solve 3/8 – 1/4. (LCM 8: 3/8 – 2/8 = 1/8)
  • Add 1/5 + 2/10. (LCM 10: 2/10 + 2/10 = 4/10 = 2/5)
  • Subtract 7/9 – 1/3. (LCM 9: 7/9 – 3/9 = 4/9)
  • Explain why we find the LCM when adding fractions with different denominators.

Notes (Expanded & Detailed):

  • Adding and subtracting fractions with like denominators is straightforward — only numerators change.
  • Unlike denominators require converting to equivalent fractions with a common denominator (usually the LCM) to add or subtract properly.
  • Simplifying the answer helps present the result in the simplest form.
  • Fraction operations are essential in daily life — cooking, measuring, sharing, and budgeting often require adding or subtracting parts of wholes.
  • Multi-step problems help build problem-solving skills by combining addition and subtraction of fractions.
  • Visual aids such as fraction strips, bars, and number lines support understanding.

Extended Practice Assignments:

  • Add and simplify these: 1/6 + 3/6, 2/9 + 4/9, 5/12 + 1/4
  • Subtract and simplify these: 7/8 – 3/8, 9/10 – 2/5, 11/15 – 4/15
  • Solve word problems involving fractions addition and subtraction (e.g., “If Jane drank 3/4 of a liter of juice and then 1/8 liter more, how much juice did she drink in total?”)
  • Create a mini-poster illustrating the steps to add fractions with unlike denominators.
  • Explain with examples why fractions must have the same denominator before adding or subtracting.

This detailed and example-rich lesson ensures students master adding and subtracting fractions both with like and unlike denominators, supported by practical activities and assessments.

C – Consolidation (Conclusion & Assessment)
Time: 5–10 minutes
Summary: To add or subtract fractions, make denominators the same, then add or subtract numerators. Simplify answers when possible.

Evaluation Method (Expanded):
Exit slip/quiz: Solve 2/3 + 1/6 and 5/8 – 1/4.
Teacher will collect slips and provide oral feedback.

Assignment (Expanded):
Solve 4/7 + 2/7, 3/5 – 1/10, and 2/3 + 3/9 – 1/3.

Follow-up Activity:
Students create real-life word problems involving addition and subtraction of fractions.

Differentiation / Inclusive Strategies
Teacher uses fraction visuals and peer teaching for learners needing extra support.

Teacher’s Reflection (After Class)
What worked well? ___________________________________________
What needs improvement? ____________________________________
Students’ engagement level: ☑ High ☑ Medium ☑ Low