Grade/Level: Primary 1 Number of Pupils in Class: 70 Date: 2026-06-28 Duration: 80 minutes
Name of Teacher: MR MASUMBA
Subject: Mathematics Theme: Basic Operations
Topic: Open Sentences (1)
Learning Outcome:
- Apply knowledge of number system to word expressions and measurement.
Focal Competence:
- Finding the missing numbers/values in open sentence questions
Performance Objective(s):
By the end of the lesson, learners should be able to:
- Apply knowledge of number system to word expressions and measurement.
- Finding the missing numbers/values in open sentence questions
Prerequisite Knowledge:
- Ability to count and identify numbers 1-10, and understand addition (+) and subtraction (-) symbols.
- Ability to solve simple addition and subtraction problems within 10.
References:
- NERDC (2014). Mathematics for Primary Schools, Book 1. Lagos: NERDC Press.
Teaching and Learning Resources:
- Not specified in the selected syllabus resources.
METHODOLOGIES, STRATEGIES AND APPROACHES:
Approach: Activity-based approach
Method:
- Discussion - Introduction, Step 3
- Demonstration - Development Step 1
- Guided Discovery - Step 2
- Practice - Step 3, Evaluation questions
Strategy:
- Whole class - Introduction, Development Step 1, Evaluation questions
- Group work - Step 2
- Pair work - Step 3
Lesson Implementation:
| Stage | Teaching Methods | Teacher Activities | Learner Activities | Learning Points |
|---|---|---|---|---|
| Introduction - 10 min | Discussion | Teacher asks learners to solve 3 + 2 = ? orally. Teacher writes on the board: 3 + __ = 5 and says, 'The blank space means a number is missing. We call this an open sentence. How can we find the missing number?' Using 5 counters, teacher removes 3 and asks learners to count the remaining. Guides learners to see that the missing number is 2. | Learners answer '5' for 3 + 2. Learners observe the open sentence 3 + __ = 5. They count the remaining counters: 1, 2. Learners say the missing number is 2. | An open sentence has a missing number that can be found. For example, 3 + __ = 5, the missing number is 2 because 3 + 2 = 5. |
| Development Step 1 - 20 min | Demonstration | Teacher draws a box (□) on the board and explains, 'This box can hold a missing number.' Writes □ + 2 = 6. Using counters, teacher lays out 6 counters, removes 2, and counts 4 left, saying 'So the box holds 4.' Writes 7 - □ = 3. Uses counters to remove 4 from 7, leaving 3, saying 'So the box holds 4 again.' | Learners watch the teacher's demonstration. They count aloud with the teacher: '4 counters left.' Learners repeat: 'The box holds 4.' They observe the subtraction example and confirm the box holds 4. | Missing numbers can be shown with a box (□). In □ + 2 = 6, □ = 4. In 7 - □ = 3, □ = 4. |
| Step 2 - 20 min | Guided Discovery | Teacher divides class into small groups and gives each group 10 counters. Displays on the board: □ + 3 = 7, 9 - □ = 5, 4 + □ = 8. Instructs groups to use counters to find the missing number for each. Moves around to assist and observe. | In groups, learners use counters to model each open sentence. For □ + 3 = 7, they count 7 counters, remove 3, find 4 left, so write □ = 4. For 9 - □ = 5, they start with 9, remove counters until 5 remain, count removed = 4. For 4 + □ = 8, they count 8, remove 4, find 4. They record their answers. | Using counters helps find missing numbers. For □ + 3 = 7, □ = 4 because 4 + 3 = 7. For 9 - □ = 5, □ = 4 because 9 - 4 = 5. For 4 + □ = 8, □ = 4 because 4 + 4 = 8. |
| Step 3 - 20 min | Discussion, Practice | Teacher writes on the board: 5 + □ = 9, □ - 3 = 2, 10 - □ = 6. Instructs learners in pairs to find the missing numbers using counters or mental methods. Calls pairs to present their answers and explain how they found them. | In pairs, learners solve each sentence: 5 + □ = 9 → □ = 4; □ - 3 = 2 → □ = 5; 10 - □ = 6 → □ = 4. They use counters if needed and explain their working. Selected pairs share with the class. | In 5 + □ = 9, □ = 4. In □ - 3 = 2, □ = 5. In 10 - □ = 6, □ = 4. |
| Evaluation questions - 10 min | Practice | Teacher asks the whole class to find the missing numbers: (1) 3 + □ = 8, (2) □ - 2 = 6, (3) 7 - □ = 4. Listens to responses and corrects any errors. | Learners solve mentally or using counters: (1) □ = 5, (2) □ = 8, (3) □ = 3. They call out their answers. | Correct answers: (1) □ = 5; (2) □ = 8; (3) □ = 3. Finding missing numbers solves open sentences. |
Lesson Evaluation:
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