Addition and Subtraction, Fractions, Decimals and Reasoning for Primary 4

Class: Primary 4
Term: 1st Term
Week: 8
Age: 9 years
Duration: 45 minutes
Subject: General Mathematics
Curriculum Theme: Numbers and Numeration
Previous Lesson: Addition of Whole Numbers, Place Value, Abacus and Missing Numbers.
Topic: ADDITION & SUBTRACTION
Subject Matter: Addition and subtraction of whole numbers, addition and subtraction of fractions, quantitative reasoning on fractions operations, addition and subtraction of decimals up to 3 decimal places, quantitative reasoning on decimal numbers.

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Revise addition of whole numbers.
• Subtract whole numbers with worked examples.
• Add and subtract fractions.
• Solve quantitative reasoning involving addition and subtraction of fractions.
• Add and subtract decimals up to 3 decimal places.
• Solve quantitative reasoning on decimal numbers.

Affective Domain:

• Show interest in performing addition and subtraction operations.
• Appreciate the importance of accuracy in calculations.

Psychomotor Domain:

• Accurately carry out addition and subtraction of whole numbers, fractions, and decimals.
• Apply addition and subtraction skills to solve quantitative reasoning problems.

Social Domain:

• Collaborate with peers to solve mathematical problems.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum for Primary Schools.
• State Unified Scheme of Work for Primary 4 Mathematics.
• New General Mathematics for Primary Schools 4.

Instructional Materials

The teacher will teach this lesson with the aid of:

• Textbook (New General Mathematics for Primary Schools 4).
• Workbook.
• Whiteboard and markers.
• Number charts.
• Flashcards with addition and subtraction problems.

Rationale for the Lesson

This lesson helps pupils to develop essential mathematical skills in addition and subtraction across different number types. Understanding these operations is fundamental for daily calculations, problem-solving, and further learning in mathematics.

Prerequisite/Previous Knowledge

Pupils have a basic understanding of numbers and simple addition and subtraction of small whole numbers.

Lesson Content/Board Summary

ADDITION AND SUBTRACTION

Addition and Subtraction of Whole Numbers

Addition is the process of combining two or more numbers to find their total sum. Subtraction is the process of taking one number away from another to find the difference.

Examples:

• Addition: 345 + 123 = 468
• Subtraction: 567 – 234 = 333

Addition and Subtraction of Fractions

To add or subtract fractions, they must have a common denominator. If the denominators are different, find the Least Common Multiple (LCM) of the denominators to make them the same.

Steps for adding/subtracting fractions:

• Find a common denominator.
• Convert the fractions to equivalent fractions with the common denominator.
• Add or subtract the numerators.
• Keep the common denominator.
• Simplify the result if possible.

Examples:

• Addition: 1/4 + 2/4 = 3/4
• Subtraction: 3/5 – 1/5 = 2/5

Quantitative Reasoning on Fractions

Quantitative reasoning on fractions involves solving word problems or number patterns that require addition or subtraction of fractions.

Example: If John ate 1/3 of a cake and Mary ate 1/3 of the same cake, what fraction of the cake did they eat altogether? (Answer: 2/3)

Addition and Subtraction of Decimals up to 3 Decimal Places

Decimals are numbers that include a whole number part and a fractional part, separated by a decimal point. To add or subtract decimals, align the decimal points vertically and then add or subtract as with whole numbers.

Steps for adding/subtracting decimals:

• Align the decimal points.
• Add zeros to the end of numbers to make them have the same number of decimal places, if necessary.
• Add or subtract from right to left, carrying or borrowing as needed.
• Place the decimal point in the answer directly below the aligned decimal points.

Examples:

• Addition: 0.25 + 0.13 = 0.38
• Subtraction: 1.50 – 0.25 = 1.25

Quantitative Reasoning on Decimals

Quantitative reasoning on decimals involves solving real-life problems or number puzzles that use decimal numbers.

Example: A tailor bought 2.5 meters of fabric and used 1.25 meters. How much fabric is left? (Answer: 1.25 meters)

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and introduces the topic by asking them to recall simple addition and subtraction facts. The teacher writes a simple addition and subtraction problem on the board (e.g., 10 + 5 = ?, 15 – 7 = ?) and asks pupils to solve them.
Pupils’ Activity: Pupils respond to greetings, recall simple facts, and solve the problems.
Learning Point: Pupils are reminded of basic addition and subtraction.

Step 2: Addition and Subtraction of Whole Numbers

Time: 7 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains addition and subtraction of whole numbers, giving examples on the board. The teacher guides pupils through a few examples, showing how to regroup (carry over) and borrow.

Examples:

• Add: 456 + 231
• Subtract: 789 – 345

Pupils’ Activity: Pupils listen, take notes, and solve examples with the teacher’s guidance.
Learning Point: Pupils revise how to add and subtract whole numbers accurately.

Step 3: Addition and Subtraction of Fractions

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains how to add and subtract fractions, emphasizing the need for a common denominator. The teacher demonstrates finding LCM and performing the operations with examples.

Examples:

• Add: 1/3 + 1/6
• Subtract: 3/4 – 1/2

Pupils’ Activity: Pupils observe the steps, ask questions, and practice solving similar problems.
Learning Point: Pupils learn to add and subtract fractions by finding a common denominator.

Step 4: Quantitative Reasoning on Fractions

Time: 5 minutes
Teaching Skill: Problem-Solving
Teacher’s Activity: The teacher presents simple quantitative reasoning problems involving addition and subtraction of fractions. The teacher guides pupils on how to interpret the problems and apply the correct operations.

Example: A baker used 1/2 cup of flour for a cake and 1/4 cup for cookies. How much flour did he use in total?

Pupils’ Activity: Pupils attempt to solve the problems and discuss their methods.
Learning Point: Pupils apply fraction operations to solve word problems.

Step 5: Addition and Subtraction of Decimals

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher introduces decimals and explains how to add and subtract them, stressing the importance of aligning the decimal points. The teacher provides examples up to 3 decimal places.

Examples:

• Add: 1.23 + 0.456
• Subtract: 5.789 – 2.34

Pupils’ Activity: Pupils listen, observe the alignment of decimal points, and solve practice problems.
Learning Point: Pupils learn to add and subtract decimals by aligning decimal points.

Step 6: Quantitative Reasoning on Decimals

Time: 5 minutes
Teaching Skill: Problem-Solving
Teacher’s Activity: The teacher provides quantitative reasoning problems involving addition and subtraction of decimals, linking them to real-life situations like money or measurements.

Example: If a pen costs N15.50 and an eraser costs N5.25, how much do they cost altogether?

Pupils’ Activity: Pupils work to solve the problems, showing their steps.
Learning Point: Pupils apply decimal operations to solve real-world problems.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define addition and subtraction.
2. Add 3,450 and 1,234.
3. Subtract 876 from 999.
4. Add 1/5 and 2/5.
5. Subtract 3/4 from 7/8.
6. Add 2.34 and 1.5.
7. Subtract 0.75 from 3.20.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarizing
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the importance of addition and subtraction in daily life and in mathematics. The teacher assigns homework from the textbook.
Pupils’ Activity: Pupils listen and copy down the homework.
Learning Point: Pupils recall the main concepts learned in the lesson.

Home Task: Solve three new exercises on ADDITION & SUBTRACTION. Show each step and check each answer.

Lesson Keywords

• Addition – Combining numbers to find a total.
• Subtraction – Taking one number away from another to find the difference.
• Whole Numbers – Counting numbers (0, 1, 2, 3…).
• Fractions – Parts of a whole (e.g., 1/2, 3/4).
• Decimals – Numbers with a decimal point, representing parts of a whole (e.g., 0.5, 1.25).
• Quantitative Reasoning – Solving problems involving numbers and quantities.
• Denominator – The bottom number in a fraction, showing the total number of equal parts.
• Numerator – The top number in a fraction, showing how many parts are being considered.

Differentiation

For pupils who grasp concepts quickly, the teacher will provide more complex problems for independent practice. For pupils needing more support, the teacher will offer one-on-one guidance, use visual aids more extensively, and simplify problems.

Note for teachers using this lesson plan

Teachers should adapt this lesson plan to suit the specific needs and learning pace of their pupils. Practical examples from pupils’ daily lives will help reinforce understanding. Encourage pupils to show their working steps clearly.