Class: Primary 1
Term: 3rd Term
Week: 2
Age: 6 years
Duration: 45 minutes
Subject: Mathematics
Curriculum Theme: Number and Numeration
Previous Lesson: Addition, Adding 2-Digit Numbers.
Topic: Subtraction
Subject Matter: Subtracting 2-digit numbers involving regrouping or “carrying over”

Specific Objectives

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

Cognitive Domain:

Arrange 2-digit numbers in Tens and Units columns for subtraction.
Carry out subtraction operations involving 2-digit numbers with regrouping.

Affective Domain:

Appreciate the importance of accuracy when subtracting numbers in daily life situations.
Show patience when solving subtraction problems that require regrouping.

Psychomotor Domain:

Solve subtraction problems like 95 – 27 and 71 – 56 correctly using the regrouping method.
Demonstrate the process of regrouping using concrete materials or drawings.

Work collaboratively with peers to solve subtraction problems.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum
State Unified Scheme of Work
New General Mathematics for Primary Schools 1
Primary Mathematics Textbook for Primary 1

Instructional Materials

The teacher will teach this lesson with the aid of:

Number charts
Place value chart (Tens and Units)
Counters or bundles of sticks
Whiteboard/chalkboard and markers/chalk
Flashcards with subtraction problems

Rationale for the Lesson

This lesson helps pupils understand how to subtract larger 2-digit numbers by using regrouping, which is a fundamental skill for more complex arithmetic. It enables them to solve practical problems involving quantities and money in their everyday lives, promoting accuracy and logical thinking.

Prerequisite/Previous Knowledge

Pupils have prior knowledge of basic subtraction of 2-digit numbers without regrouping and can identify Tens and Units in numbers.

Lesson Content/Board Summary

Subtraction of 2-Digit Numbers with Regrouping (Borrowing)

What is Regrouping in Subtraction?

Regrouping, also called borrowing, is when we take one Ten from the Tens column and change it into ten Units to help us subtract in the Units column when the top digit is smaller than the bottom digit.

Steps for Subtracting with Regrouping:

Step 1: Arrange the numbers in Tens (T) and Units (U) columns.
Step 2: Start subtracting from the Units column.
Step 3: If the top digit in the Units column is smaller than the bottom digit, “borrow” one Ten from the Tens column. This one Ten becomes 10 Units and is added to the Units column.
Step 4: Subtract the Units.
Step 5: Move to the Tens column. Remember to subtract 1 from the top digit in the Tens column because you “borrowed” from it.
Step 6: Subtract the Tens.

Examples:

Example 1: Subtract 27 from 95

T U
9 5
– 2 7
—–

Step 1: Arrange 95 and 27 in T U columns.
Step 2: In the Units column, we have 5 – 7. We cannot subtract 7 from 5.
Step 3: Regroup (borrow) 1 Ten from 9 Tens. The 9 Tens become 8 Tens. The 1 Ten borrowed becomes 10 Units. Add 10 Units to the 5 Units, making it 15 Units.
Step 4: Subtract the Units: 15 – 7 = 8. Write 8 in the Units column.
Step 5: In the Tens column, we now have 8 (from the original 9) – 2.
Step 6: Subtract the Tens: 8 – 2 = 6. Write 6 in the Tens column.

T U
⁸9 ¹⁵5
– 2 7
—–
6 8

So, 95 – 27 = 68.

Example 2: Subtract 56 from 71

T U
7 1
– 5 6
—–

Step 1: Arrange 71 and 56 in T U columns.
Step 2: In the Units column, we have 1 – 6. We cannot subtract 6 from 1.
Step 3: Regroup (borrow) 1 Ten from 7 Tens. The 7 Tens become 6 Tens. The 1 Ten borrowed becomes 10 Units. Add 10 Units to the 1 Unit, making it 11 Units.
Step 4: Subtract the Units: 11 – 6 = 5. Write 5 in the Units column.
Step 5: In the Tens column, we now have 6 (from the original 7) – 5.
Step 6: Subtract the Tens: 6 – 5 = 1. Write 1 in the Tens column.

T U
⁶7 ¹¹1
– 5 6
—–
1 5

So, 71 – 56 = 15.

Everyday Life Examples Where Accuracy in Subtraction is Needed:

Accuracy in subtraction is important in many daily situations, such as:

Calculating change when buying items.
Figuring out how many items are left after some have been used.
Determining how many more points a team needs to win a game.
Counting how many days are left until an event.
Managing small amounts of money or resources.

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 reviews the previous lesson on simple subtraction without regrouping. The teacher then introduces the new topic: “Subtraction of 2-Digit Numbers with Regrouping.”
Pupils’ Activity: Pupils respond to greetings, recall previous knowledge, and listen attentively to the new topic.
Learning Point: Pupils are prepared for the new lesson and connect it to prior learning.

Step 2: Explanation of Regrouping

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher uses a place value chart and bundles of sticks/counters to explain what regrouping (borrowing) means. The teacher shows how one Ten can be exchanged for ten Units.
Pupils’ Activity: Pupils observe the demonstration and ask questions for clarification.
Learning Point: Pupils understand the concept of regrouping in subtraction.

Step 3: Demonstration of Subtraction with Regrouping

Time: 10 minutes
Teaching Skill: Demonstration
Teacher’s Activity: The teacher writes an example like 95 – 27 on the board, arranges it in T U columns, and demonstrates the step-by-step process of subtracting with regrouping, explaining each action clearly.
Pupils’ Activity: Pupils watch carefully and follow the steps as the teacher demonstrates.
Learning Point: Pupils learn the correct procedure for subtracting 2-digit numbers with regrouping.

Step 4: Guided Practice

Time: 8 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher writes another example, 71 – 56, on the board and guides the pupils to solve it together, asking questions at each step to ensure understanding.
Pupils’ Activity: Pupils participate actively, suggesting steps and solving the problem with the teacher’s guidance.
Learning Point: Pupils practice the regrouping method with support.

Step 5: Independent Practice

Time: 7 minutes
Teaching Skill: Individual Work
Teacher’s Activity: The teacher gives pupils a similar problem (e.g., 83 – 39) to solve individually in their notebooks. The teacher moves around to provide assistance.
Pupils’ Activity: Pupils solve the given subtraction problem independently.
Learning Point: Pupils apply the learned steps independently.

Step 6: Real-life Applications

Time: 5 minutes
Teaching Skill: Discussion
Teacher’s Activity: The teacher discusses everyday situations where subtraction with regrouping is necessary, such as calculating change or finding out how many items are left.
Pupils’ Activity: Pupils suggest their own examples and listen to the teacher’s examples.
Learning Point: Pupils understand the practical relevance of subtraction.

Step 7: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Arrange the numbers 64 and 28 in Tens and Units columns.
Explain what you do when the top digit in the Units column is smaller than the bottom digit during subtraction.
Solve: 52 – 17.
Mention two everyday situations where you might need to use subtraction with regrouping.

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, emphasizing the importance of regrouping when the top digit is smaller. The teacher assigns homework.
Pupils’ Activity: Pupils listen to the summary and copy the homework.
Learning Point: Pupils consolidate their learning and prepare for further practice.

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

Lesson Keywords

Subtraction – Taking one number away from another.
Regrouping – Exchanging one Ten for ten Units to help subtract.
Borrowing – Another word for regrouping in subtraction.
Tens – The column representing groups of ten.
Units – The column representing single items.
Difference – The answer to a subtraction problem.

Differentiation

For struggling learners, the teacher will provide extra one-on-one support and use more concrete manipulatives. They will be given simpler problems with smaller numbers. Advanced learners will be given more challenging problems or word problems that require applying subtraction with regrouping in context.

Note for teachers using this lesson plan

Ensure pupils have a solid understanding of place value before introducing regrouping. Use visual aids and hands-on materials extensively to make the abstract concept of regrouping concrete. Encourage pupils to explain their steps to reinforce their understanding. Provide ample practice opportunities both in class and for homework.