Addition and Subtraction of Fractions Mathematics Primary 5 First Term Lesson Notes Week 9
Mathematics Primary 5 First Term Lesson Notes
Week: 9
Subject: Mathematics
Class: Primary 5
Term: First Term
Age: 10 years
Topic: Addition and Subtraction of Fractions
Sub-Topics:
- Addition of Fractions and Mixed Numbers
- Subtraction of Fractions and Mixed Numbers
- Addition and Subtraction of Decimal Fractions
- Real-Life Problems
- Quantitative Reasoning
Duration: 40 minutes
Behavioural Objectives:
By the end of the lesson, pupils should be able to:
- Add and subtract fractions with common denominators.
- Add and subtract proper fractions, improper fractions, and mixed fractions.
- Solve real-life problems involving addition and subtraction of fractions.
- Use the LCM method to add and subtract fractions.
- Apply quantitative aptitude to problems related to addition and subtraction of mixed numbers.
Keywords:
- Fractions
- Mixed numbers
- Decimal fractions
- Addition
- Subtraction
- Real-life problems
Set Induction:
The teacher will start with a discussion on how fractions are used in everyday life, such as cooking or shopping, to introduce the importance of adding and subtracting fractions.
Entry Behaviour:
Pupils should be familiar with basic fractions and simple addition and subtraction.
Learning Resources and Materials:
- Fraction charts
- Worksheets for practice
- Visual aids for mixed numbers
- Whiteboard and markers
Building Background/Connection to Prior Knowledge: The teacher will review basic fraction operations and introduce mixed numbers and decimal fractions.
Embedded Core Skills:
- Problem-solving
- Analytical thinking
- Application of mathematical operations
Learning Materials:
- Fraction charts
- Practice worksheets
- Visual aids
Reference Books:
Lagos State Scheme of Work, Primary 5 Mathematics Textbook
Instructional Materials:
- Fraction charts
- Worksheets
- Whiteboard and markers
Content:
- Addition of Fractions and Mixed Numbers
- Adding fractions with common denominators.
- Adding mixed numbers.
- Examples and practice problems.
- Subtraction of Fractions and Mixed Numbers
- Subtracting fractions with common denominators.
- Subtracting mixed numbers.
- Examples and practice problems.
- Addition and Subtraction of Decimal Fractions
- Adding and subtracting decimal fractions.
- Examples and practice problems.
- Real-Life Problems
- Applying addition and subtraction of fractions to real-life scenarios.
- Examples and practice problems.
- Quantitative Reasoning
- Solving quantitative aptitude problems involving fractions and mixed numbers.
- Examples and practice problems.
Addition of Fractions and Mixed Numbers
Adding Fractions with Common Denominators:
- To add fractions with the same denominator, keep the denominator and add the numerators.
Examples:
- 3/8 + 2/8 = 5/8
- 7/10 + 1/10 = 8/10, which simplifies to 4/5
- 5/12 + 3/12 = 8/12, which simplifies to 2/3
- 4/7 + 2/7 = 6/7
- 9/15 + 4/15 = 13/15
Adding Mixed Numbers:
- Add the whole numbers together and then add the fractions. If needed, convert any improper fractions to mixed numbers.
Examples:
- 2 1/4 + 1 2/4 = 3 3/4
- 5 3/8 + 2 5/8 = 8 1/4
- 7 2/5 + 3 4/5 = 11 1/5
- 4 7/10 + 2 1/10 = 6 4/10, which simplifies to 6 2/5
- 3 3/6 + 4 4/6 = 7 1/6
Class Work:
- 5/9 + 2/9 = ?
- 3 1/3 + 2 2/3 = ?
- 6/11 + 4/11 = ?
- 1 5/8 + 3 1/8 = ?
- 7/12 + 2/12 = ?
Subtraction of Fractions and Mixed Numbers
Subtracting Fractions with Common Denominators:
- To subtract fractions with the same denominator, keep the denominator and subtract the numerators.
Examples:
- 7/8 – 3/8 = 4/8, which simplifies to 1/2
- 5/6 – 2/6 = 3/6, which simplifies to 1/2
- 9/10 – 4/10 = 5/10, which simplifies to 1/2
- 11/12 – 1/12 = 10/12, which simplifies to 5/6
- 8/15 – 3/15 = 5/15, which simplifies to 1/3
Subtracting Mixed Numbers:
- Subtract the whole numbers and then subtract the fractions. Borrow from the whole number if needed.
Examples:
- 5 3/4 – 2 1/4 = 3 2/4, which simplifies to 3 1/2
- 7 2/5 – 4 1/5 = 3 1/5
- 9 1/6 – 3 5/6 = 5 1/6
- 6 4/7 – 2 3/7 = 4 1/7
- 8 3/10 – 4 7/10 = 3 6/10, which simplifies to 3 3/5
Class Work:
- 7/8 – 2/8 = ?
- 6 1/2 – 3 3/4 = ?
- 9/10 – 1/10 = ?
- 4 5/6 – 2 2/6 = ?
- 8/12 – 3/12 = ?
Addition and Subtraction of Decimal Fractions
Adding and Subtracting Decimal Fractions:
- Align the decimal points and add or subtract as you would with whole numbers. Place the decimal point in the result.
Examples:
- 3.45 + 2.30 = 5.75
- 7.89 – 4.56 = 3.33
- 12.50 + 7.25 = 19.75
- 15.60 – 8.40 = 7.20
- 6.75 + 3.85 = 10.60
Class Work:
- 4.25 + 3.50 = ?
- 9.80 – 2.30 = ?
- 8.60 + 7.15 = ?
- 11.45 – 5.60 = ?
- 7.30 + 2.40 = ?
Real-Life Problems
Applying Addition and Subtraction of Fractions to Real-Life Scenarios:
- Use fractions in practical situations like cooking or measuring.
Examples:
- You have 3/4 of a cup of sugar and use 1/2 cup. How much sugar is left?
- Solution: 3/4 – 1/2 = 1/4 cup remaining.
- A pizza was divided into 8/12 and you ate 3/12. How much pizza is left?
- Solution: 8/12 – 3/12 = 5/12 remaining.
- You have 2 1/2 liters of juice and pour 1 1/4 liters. How much juice is left?
- Solution: 2 1/2 – 1 1/4 = 1 1/4 liters left.
- If you need 5/8 of a meter of ribbon for each gift and have 2 meters, how many gifts can you make?
- Solution: 2 ÷ 5/8 = 3 1/5 gifts.
- You buy 1 1/2 meters of fabric and use 1 1/4 meters. How much fabric remains?
- Solution: 1 1/2 – 1 1/4 = 1/4 meter remaining.
Class Work:
- You have 2 1/2 hours to study and spend 1 3/4 hours. How much time is left?
- You bake 5/6 of a cake and eat 2/6. How much is left?
- You need 3/5 of a liter of milk for a recipe. If you have 2 liters, how much is left?
- You have 4 liters of juice and pour 7/8 liters into a jug. How much is left?
- You buy 1 1/2 meters of fabric and use 1 1/4 meters. How much fabric remains?
Quantitative Reasoning
Solving Quantitative Aptitude Problems Involving Fractions and Mixed Numbers:
Examples:
- If a car travels 3 1/2 miles in an hour, how far does it travel in 4 1/2 hours?
- Solution: 3 1/2 × 4 1/2 = 15 1/4 miles.
- A job takes 5 1/3 hours to complete and 4 1/2 workers are assigned. How long will it take?
- Solution: 5 1/3 ÷ 4 1/2 = 1 5/6 hours.
- If you mix 2 1/4 liters with 3 2/3 liters, what is the total mixture?
- Solution: 2 1/4 + 3 2/3 = 6 1/12 liters.
- A recipe requires 2/5 cup of salt and you have 3/4 cup. How much salt is left?
- Solution: 3/4 – 2/5 = 7/20 cup remaining.
- If a book has 250 pages and you read 3/5 of it, how many pages have you read?
- Solution: 250 × 3/5 = 150 pages.
Class Work:
- Calculate 2 1/4 × 3 2/5.
- Find the time taken if a task needs 7 1/2 hours and 3 workers are assigned.
- Determine the remaining mixture if 5 1/4 liters are added to 6 2/3 liters.
- Subtract 3/7 from 5/6.
- If 4/5 of 200 pages are read, how many pages are read?
Questions
- The sum of 1/4 and 2/4 is __________.
a) 3/4
b) 2/4
c) 1/2
d) 1 - Subtract 3/8 from 5/8. The result is __________.
a) 2/8
b) 1/2
c) 3/8
d) 1/4 - Adding 2 1/2 and 3 1/4 gives __________.
a) 5 1/4
b) 5 3/4
c) 6
d) 6 1/4 - Subtract 1 3/5 from 4 2/5. The result is __________.
a) 2
b) 3 2/5
c) 3
d) 2 2/5 - The sum of 0.5 and 1.75 is __________.
a) 2.25
b) 2.5
c) 1.75
d) 1.25 - Subtract 2.6 from 5.4. The result is __________.
a) 3.8
b) 2.8
c) 3
d) 2.6 - Add 1/3 and 1/6. The result is __________.
a) 1/2
b) 2/6
c) 1/3
d) 1/6 - Subtract 5/10 from 8/10. The result is __________.
a) 1/10
b) 3/10
c) 1/2
d) 1 - Adding 2 2/5 and 3 3/5 gives __________.
a) 5 1/5
b) 5 2/5
c) 6
d) 5 4/5 - Subtract 7 3/4 from 10 1/4. The result is __________.
a) 2 1/2
b) 3
c) 2 3/4
d) 3 1/4 - The sum of 0.2 and 0.4 is __________.
a) 0.6
b) 0.8
c) 0.4
d) 0.2 - Subtract 1.9 from 3.5. The result is __________.
a) 1.6
b) 1.5
c) 2.4
d) 2.0 - Add 3/7 and 2/7. The result is __________.
a) 5/7
b) 6/7
c) 1
d) 1/7 - Subtract 4/9 from 5/6. The result is __________.
a) 1/6
b) 1/9
c) 7/18
d) 5/18 - Adding 3.25 and 2.4 gives __________.
a) 5.65
b) 5.6
c) 5.5
d) 5.75
Class Activity Discussion
- Q: How do you add fractions with different denominators?
A: Find the least common denominator, convert the fractions, then add the numerators. - Q: What is the procedure for subtracting mixed numbers?
A: Subtract the whole numbers first, then subtract the fractions. If needed, borrow from the whole number. - Q: How do you convert fractions to decimal fractions?
A: Divide the numerator by the denominator. - Q: What is the LCM method for adding fractions?
A: Find the least common multiple of the denominators to create a common denominator. - Q: How do you handle subtraction of decimal fractions?
A: Line up the decimal points and subtract as you would with whole numbers. - Q: How do you simplify a fraction after addition or subtraction?
A: Reduce the fraction to its simplest form by dividing the numerator and denominator by their greatest common divisor. - Q: What if the fractions have different denominators when subtracting?
A: Convert to a common denominator, then subtract the numerators. - Q: How can you solve real-life problems with fractions?
A: Apply fraction operations to scenarios like measuring ingredients or dividing quantities. - Q: Why is it important to convert mixed numbers to improper fractions?
A: It simplifies the process of addition and subtraction. - Q: How do you check your answer after adding or subtracting fractions?
A: Verify that the result is simplified and check by converting it to a decimal if needed. - Q: What should you do if you need to borrow when subtracting mixed numbers?
A: Borrow from the whole number part and convert it to a fraction. - Q: How can decimal fractions be converted back to fractions?
A: Write the decimal as a fraction with a denominator based on the place value, then simplify. - Q: How do you handle addition and subtraction of fractions with unlike denominators?
A: Convert to a common denominator before performing the operation. - Q: How do you add mixed numbers with different denominators?
A: Convert to improper fractions, find a common denominator, and then add. - Q: What are some practical applications of fractions in everyday life?
A: Cooking recipes, measuring materials, dividing items, and financial calculations.
Presentation:
Step 1: Review the basic operations with fractions and mixed numbers.
Step 2: Demonstrate how to add and subtract decimal fractions.
Step 3: Solve real-life problems using the operations learned.
Teacher’s Activities:
- Explain and demonstrate addition and subtraction of fractions and mixed numbers.
- Provide examples and practice problems.
- Guide pupils through real-life scenarios and quantitative problems.
Learners’ Activities:
- Participate in solving examples of fraction operations.
- Complete worksheets and real-life problem scenarios.
- Practice quantitative reasoning problems.
Assessment:
- Solve addition problems involving fractions and mixed numbers.
- Perform subtraction with fractions and mixed numbers.
- Apply the LCM method to add and subtract fractions.
- Solve real-life problems using addition and subtraction of fractions.
Evaluation Questions:
- What is the sum of 3/5 and 2/5?
- Subtract 1/8 from 7/8.
- Add 4 1/2 and 3 3/4.
- What is 5 1/3 minus 2 2/3?
- Convert 0.75 to a fraction.
- Subtract 0.5 from 2.3.
- Add 2 1/4 and 1 2/3.
- Subtract 1 3/5 from 4 1/5.
- What is the decimal equivalent of 1/4?
- Add 0.2 and 0.4.
- Subtract 3/10 from 7/10.
- Convert 1.2 to a fraction.
- What is the sum of 2 2/5 and 1 1/5?
- Subtract 1.1 from 4.5.
- What is 0.6 plus 0.9?
Conclusion:
The teacher will review answers, provide feedback, and clarify any misunderstandings. Pupils will discuss the real-life applications of fractions and their importance in everyday activities.
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