Class: Primary 1
Term: Third Term
Week: 1
Age: 6 years
Duration: 45 minutes
Subject: Mathematics
Previous Lesson:
Curriculum Theme: Number and Numeration
Previous Lesson: Addition of 2-digit numbers without regrouping.
Topic: Addition
Subject Matter: Adding 2-digit numbers with sum less than 100 involving regrouping or “carrying over”

Specific Objectives

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

Cognitive Domain:

Identify the place values (Tens and Units) in 2-digit numbers.
Arrange 2-digit numbers vertically according to their place values for addition.
Add 2-digit numbers with regrouping (carrying over) where the sum is less than 100.

Affective Domain:

Show interest and confidence in solving addition problems involving regrouping.
Develop accuracy when performing addition operations.

Psychomotor Domain:

Neatly write down 2-digit numbers for addition.
Solve addition problems involving regrouping correctly.

Work cooperatively with peers to solve addition problems.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Primary 1 Mathematics
State Unified Scheme of Work for Primary 1 Mathematics
New Method Mathematics for Primary Schools 1
Teacher’s Guide for Primary 1 Mathematics

Instructional Materials

The teacher will teach this lesson with the aid of:

Place value chart
Counters or bottle tops
Bundles of sticks (in tens and loose ones)
Chalk and chalkboard

Rationale for the Lesson

This lesson is important because it builds on pupils’ foundational understanding of addition, introducing them to a necessary skill for more complex calculations. Understanding regrouping helps pupils solve practical daily problems involving combining quantities, such as counting money or objects.

Prerequisite/Previous Knowledge

Pupils are expected to have prior knowledge of:

Identifying Tens and Units in 2-digit numbers.
Adding 2-digit numbers without regrouping.
Basic addition facts up to 10.

Lesson Content/Board Summary

Addition of 2-Digit Numbers with Regrouping (Carrying Over)

Understanding Place Value

Every 2-digit number has two place values:

Units (U): The digit on the right, representing single items.
Tens (T): The digit on the left, representing groups of ten.

Steps for Adding 2-Digit Numbers with Regrouping

When adding 2-digit numbers with regrouping, follow these steps:

Step 1: Arrange the numbers vertically, aligning the Units under Units and the Tens under Tens.
Step 2: Start adding the digits in the Units column first.
Step 3: If the sum of the Units digits is 10 or more, write down the Units digit of the sum and “carry over” the Tens digit to the Tens column.
Step 4: Add the digits in the Tens column, including any digit that was carried over.

Worked Examples

Let us solve some examples:

Example 1: Add 15 and 57

Step 1: Arrange the numbers by place value.

    T U
    1 5
  + 5 7
  -----

Step 2: Add the Units digits (5 + 7).

5 + 7 = 12. Write down 2 in the Units column and carry over 1 to the Tens column.

    T U
    ¹1 5  (¹ is the carried over ten)
  + 5 7
  -----
      2

Step 3: Add the Tens digits (1 + 5 + 1 carried over).

1 + 5 + 1 = 7. Write down 7 in the Tens column.

    T U
    ¹1 5
  + 5 7
  -----
    7 2

So, 15 + 57 = 72.

Example 2: Add 27 and 63

Step 1: Arrange the numbers by place value.

    T U
    2 7
  + 6 3
  -----

Step 2: Add the Units digits (7 + 3).

7 + 3 = 10. Write down 0 in the Units column and carry over 1 to the Tens column.

    T U
    ¹2 7  (¹ is the carried over ten)
  + 6 3
  -----
      0

Step 3: Add the Tens digits (2 + 6 + 1 carried over).

2 + 6 + 1 = 9. Write down 9 in the Tens column.

    T U
    ¹2 7
  + 6 3
  -----
    9 0

So, 27 + 63 = 90.

Teaching Methods/Instructional Techniques

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

Instructional Procedures

Lesson: Addition of 2-Digit Numbers with Regrouping

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and reviews the previous lesson on adding 2-digit numbers without regrouping, asking a simple question like “What is 23 + 14?”.
Pupils’ Activity: Pupils respond to the greeting and answer the review question.
Learning Point: Pupils recall prior knowledge on addition.

Step 2: Explanation of Place Value

Time: 5 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher uses a place value chart and bundles of sticks to explain Tens and Units, showing that 10 units make 1 ten.
Pupils’ Activity: Pupils observe the demonstration and identify Tens and Units in given numbers.
Learning Point: Pupils understand the concept of place value for 2-digit numbers.

Step 3: Introduction to Regrouping

Time: 8 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher demonstrates how to combine units that sum up to more than 9, explaining the concept of “carrying over” a ten to the tens column using counters or bundles of sticks. For example, combining 5 sticks and 7 sticks makes 12 sticks, which is 1 bundle of ten and 2 loose ones.
Pupils’ Activity: Pupils pay attention and ask questions for clarification.
Learning Point: Pupils grasp the idea of regrouping or carrying over.

Step 4: Guided Practice (Example 1)

Time: 10 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher writes the first example (15 + 57) on the board. The teacher guides pupils step-by-step to arrange the numbers, add the units, regroup, and then add the tens, emphasizing the “carry over” process.
Pupils’ Activity: Pupils follow along, participate in solving, and copy the example into their notes.
Learning Point: Pupils learn the structured method for adding with regrouping.

Step 5: Guided Practice (Example 2)

Time: 7 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher presents the second example (27 + 63) and guides pupils through the addition process with regrouping, similar to the first example.
Pupils’ Activity: Pupils actively participate in solving the problem and copy the example.
Learning Point: Pupils reinforce their understanding and skill in addition with regrouping.

Step 6: Class Activity/Independent Practice

Time: 5 minutes
Teaching Skill: Group Work/Monitoring
Teacher’s Activity: The teacher writes 2-3 simple addition problems with regrouping on the board for pupils to solve individually or in pairs. The teacher walks around to monitor and provide support.
Pupils’ Activity: Pupils attempt to solve the problems.
Learning Point: Pupils practice and apply the learned skill independently.

Step 7: Evaluation/Review

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

What is “regrouping” in addition?
Arrange the numbers 34 and 28 vertically for addition.
Add 34 + 28.
Explain how you carry over a number when adding.

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 lesson by reiterating the importance of place value and the steps for adding 2-digit numbers with regrouping. The teacher gives 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 Addition. Show each step and check each answer.

Lesson Keywords

Addition – The process of combining two or more numbers to find their total sum.
Regrouping – The process of exchanging 10 units for 1 ten, or 10 tens for 1 hundred, in place value.
Carry over – The digit that is moved from one column to the next column of higher place value during addition.
Tens – The place value representing groups of ten.
Units – The place value representing single items, also called ones.
Sum – The result of an addition operation.

Differentiation

For pupils who are struggling, the teacher will provide extra practice with concrete materials like counters and a place value mat to physically demonstrate regrouping. For advanced learners, the teacher will provide slightly more challenging problems or encourage them to create their own addition problems with regrouping.

Note for teachers using this lesson plan

Ensure that pupils have a strong grasp of basic addition facts and place value before introducing regrouping. Use plenty of concrete manipulatives and visual aids to make the abstract concept of carrying over tangible for Primary 1 pupils. Encourage pupils to explain their steps orally to reinforce their understanding.