Addition and Subtraction for Primary 1

Class: Primary 1
Term: 1st Term
Week: 8
Age: 6 years
Duration: 45 minutes
Subject: Mathematics
Curriculum Theme: Number and Numeration
Previous Lesson: Addition and Subtraction, Finding Missing Numbers in Open Sentences.
Topic: Addition and Subtraction (Continued)
Subject Matter: Addition and subtraction operations using place value not exceeding tens and unit (T-U)

Specific Objectives

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

Cognitive Domain:

• Define place value for tens and units.
• Arrange two-digit numbers correctly in Tens and Units (T-U) columns.
• Solve addition problems involving two-digit numbers with and without carrying.
• Solve subtraction problems involving two-digit numbers with and without borrowing.

Affective Domain:

• Show interest in performing addition and subtraction operations.
• Appreciate the importance of place value in accurate calculations.

Psychomotor Domain:

• Accurately perform addition of two-digit numbers using T-U arrangement.
• Accurately perform subtraction of two-digit numbers using T-U arrangement.
• Write down solutions neatly in their exercise books.

Social Domain:

• Work cooperatively with peers to solve given problems.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum for Mathematics Primary 1-3.
• State Unified Scheme of Work.
• Primary Mathematics Textbook 1.

Instructional Materials

The teacher will teach this lesson with the aid of:

• Number charts
• Counters (e.g., bottle tops, stones)
• Flashcards with addition and subtraction problems
• Whiteboard or blackboard
• Markers or chalk

Rationale for the Lesson

This lesson helps pupils understand how to add and subtract two-digit numbers using place value. It enables them to perform basic calculations more efficiently and forms a foundation for more complex mathematical operations in their daily lives.

Prerequisite/Previous Knowledge

Pupils can count numbers, identify single-digit numbers, and perform simple addition and subtraction of single-digit numbers.

Lesson Content/Board Summary

Addition and Subtraction Using Place Value (Tens and Units)

Understanding Tens and Units (T-U)

Place value tells us the value of each digit in a number based on its position. For two-digit numbers, we have Tens (T) and Units (U).

Example:

• In the number 25, ‘2’ is in the Tens place (20) and ‘5’ is in the Units place (5).
• In the number 86, ‘8’ is in the Tens place (80) and ‘6’ is in the Units place (6).

Addition Using Place Value (T-U)

To add numbers using place value, arrange them in columns: Units under Units, Tens under Tens. Always start adding from the Units column.

Example 1: Add 56 and 22

T U
5 6
+ 2 2
—–
7 8

Step 1: Add the Units: 6 + 2 = 8. Write 8 under the Units column.
Step 2: Add the Tens: 5 + 2 = 7. Write 7 under the Tens column.

Example 2: Add 37 and 15 (with carrying)

T U
3 7
+ 1 5
—–
5 2

Step 1: Add the Units: 7 + 5 = 12. Write 2 under the Units column and carry 1 to the Tens column.
Step 2: Add the Tens: 3 + 1 + (carried 1) = 5. Write 5 under the Tens column.

Subtraction Using Place Value (T-U)

To subtract numbers using place value, arrange them in columns: Units under Units, Tens under Tens. Always start subtracting from the Units column.

Example 1: Subtract 12 from 86

T U
8 6
− 1 2
—–
7 4

Step 1: Subtract the Units: 6 – 2 = 4. Write 4 under the Units column.
Step 2: Subtract the Tens: 8 – 1 = 7. Write 7 under the Tens column.

Example 2: Subtract 18 from 43 (with borrowing)

T U
3 13 (borrowed)
4 3
− 1 8
—–
2 5

Step 1: Subtract the Units: We cannot subtract 8 from 3. Borrow 1 Ten (10 Units) from the Tens column. The 4 Tens become 3 Tens, and the 3 Units become 13 Units. Now subtract: 13 – 8 = 5. Write 5 under the Units column.
Step 2: Subtract the Tens: Now subtract the Tens: 3 – 1 = 2. Write 2 under the Tens column.

Teaching Methods/Instructional Techniques

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

Instructional Procedures

Addition and Subtraction Using Place Value (Tens and Units)

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils, reviews the previous lesson on simple addition and subtraction, and then introduces the topic of adding and subtracting using place value (Tens and Units).
Pupils’ Activity: Pupils respond to greetings and recall previous knowledge.
Learning Point: Pupils connect the new lesson to their prior understanding of numbers.

Step 2: Explanation of Place Value (T-U)

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains the concept of Tens and Units using a place value chart and examples like 23 (2 Tens, 3 Units).
Pupils’ Activity: Pupils listen attentively, identify Tens and Units in numbers given by the teacher, and ask questions for clarity.
Learning Point: Pupils understand the concept of Tens and Units in two-digit numbers.

Step 3: Demonstration of Addition (T-U)

Time: 10 minutes
Teaching Skill: Demonstration/Modeling
Teacher’s Activity: The teacher demonstrates how to arrange numbers in T-U columns and solve addition problems on the board, including examples with carrying (e.g., 37 + 15).
Pupils’ Activity: Pupils observe the demonstration, ask questions, and copy the worked examples into their notebooks.
Learning Point: Pupils learn the step-by-step process of adding two-digit numbers using place value, including carrying.

Step 4: Guided Practice (Addition)

Time: 5 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher provides a few addition problems (e.g., 24 + 35, 46 + 28) for pupils to solve in pairs or individually, offering guidance as needed.
Pupils’ Activity: Pupils attempt to solve the problems in their exercise books with the teacher’s help.
Learning Point: Pupils practice and reinforce their addition skills using the T-U method.

Step 5: Demonstration of Subtraction (T-U)

Time: 10 minutes
Teaching Skill: Demonstration/Modeling
Teacher’s Activity: The teacher demonstrates how to arrange numbers in T-U columns and solve subtraction problems on the board, including examples with borrowing (e.g., 43 – 18).
Pupils’ Activity: Pupils observe the demonstration, ask questions, and copy the worked examples into their notebooks.
Learning Point: Pupils learn the step-by-step process of subtracting two-digit numbers using place value, including borrowing.

Step 6: Guided Practice (Subtraction)

Time: 5 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher provides a few subtraction problems (e.g., 58 – 23, 61 – 34) for pupils to solve, offering guidance and correction.
Pupils’ Activity: Pupils attempt to solve the problems in their exercise books with the teacher’s help.
Learning Point: Pupils practice and reinforce their subtraction skills using the T-U method.

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. What does ‘T’ stand for in T-U?
2. What does ‘U’ stand for in T-U?
3. Add: T U 3 6 + 1 8
4. Subtract: T U 5 4 – 2 7

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson and gives homework involving more addition and subtraction problems using T-U.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their learning and prepare for independent practice.

Home Task: Solve two new exercises on Addition and Subtraction (Continued). Show each step and check each answer.

Lesson Keywords

• Place value – The value of a digit based on its position in a number.
• Tens – The second digit from the right in a whole number, representing groups of ten.
• Units – The first digit from the right in a whole number, representing single items.
• Addition – The process of combining numbers to find their total sum.
• Subtraction – The process of taking one number away from another to find the difference.
• Carry over – Moving a group of ten from the Units column to the Tens column during addition.
• Borrowing – Taking a group of ten from the Tens column to the Units column during subtraction.

Differentiation

For pupils who are struggling, the teacher will provide additional support using concrete counters and more one-on-one guidance. Advanced learners will be given more challenging problems, including simple word problems, to apply their understanding.

Note for teachers using this lesson plan

Ensure pupils arrange numbers neatly in columns to avoid errors. Emphasize starting calculations from the Units column. Encourage mental calculation for simple problems once the concept is grasped.