Mathematics Primary 1 Second Term Lesson Notes – Week 6
Subject: Mathematics
Class: Primary 1
Term: Second Term
Week: 6
Age: 5 – 6 years
Topic: Subtraction of Numbers
Sub-topic: Subtracting One- and Two-Digit Numbers (Up to 20)
Duration: 40 minutes
Behavioural Objectives
By the end of this lesson, pupils should be able to:
- Define subtraction as taking away from a total.
- Identify the subtraction sign (–) and equals sign (=).
- Solve subtraction problems using objects and numbers.
- Subtract one-digit numbers from one-digit numbers.
- Subtract smaller numbers from larger numbers correctly.
- Apply subtraction to real-life examples.
- Write subtraction statements correctly.
- Use objects like bottle tops or sticks to demonstrate subtraction.
- Participate actively in subtraction games.
- Show confidence in solving subtraction exercises.
Keywords and Meanings
- Subtraction – Taking away one number from another.
- Minus (–) – The sign used for subtraction.
- Equals (=) – Shows the answer or result.
- Difference – The result when numbers are subtracted.
- Take Away – To remove or reduce a number.
- Left – What remains after subtraction.
- Less Than – A smaller number compared to another.
- Count Backward – Counting down when subtracting.
- Number Line – A line used to show subtraction.
- Zero – Nothing left after taking all away.
Set Induction (Storytelling Approach)
The teacher begins with a lively story:
“Last Sunday, Amina’s mother gave her 10 sweets. She ate 3 sweets after lunch. How many sweets were left?”
The teacher draws 10 sweets on the board, crosses out 3, and asks:
“How many sweets remain?”
Pupils shout: “7!”
The teacher smiles and says, “Yes! That is subtraction—taking away to know what is left.”
This immediately connects to the pupils’ world of sharing sweets, biscuits, and toys.
Entry Behaviour
Pupils have already learned how to add numbers up to 20 and can count forward and backward between 1 and 20.
Learning Resources and Materials
- Flashcards (1–20)
- Counters, sticks, bottle tops, or toy blocks
- Number line chart
- Subtraction flashcards and worksheets
- Whiteboard and marker
Building Background / Connection to Prior Knowledge
The teacher reminds pupils of their previous lesson on addition. Then says:
“If addition means putting numbers together, subtraction means taking away numbers.”
The teacher demonstrates using sticks—adding and removing them to show what remains.
Embedded Core Skills
- Numeracy Skills – Counting, reasoning, and calculating.
- Critical Thinking Skills – Using logic to find what’s left.
- Communication Skills – Explaining how they got the answers.
- Collaboration – Working in pairs to solve subtraction problems.
- Creativity – Using play materials to demonstrate.
Reference Books
- Lagos State Unified Scheme of Work
- New Method Mathematics for Primary Schools (Book 1)
- Basic Mathematics Made Easy (UBE Edition)
Instructional Materials
- Bottle tops
- Counters or sticks
- Subtraction number line
- Chart paper showing subtraction examples
Content Development
Meaning of Subtraction
Subtraction is the process of taking one number away from another to find what remains.
It helps us know how many are left after removing some items.
Signs of Subtraction
- The minus sign (–) means take away.
- The equals sign (=) shows the answer or total left.
Examples of Subtraction
- 6 – 1 = 5
- 9 – 5 = 4
- 11 – 5 = 6
- 12 – 3 = 9
- 14 – 3 = 11
- 16 – 7 = 9
- 18 – 9 = 9
- 10 – 6 = 4
- 18 – 6 = 12
- 19 – 8 = 11
More Detailed Explanation
Example 1:
There are 8 pencils on the table. If 3 are taken away, 5 are left.
8 – 3 = 5
Example 2:
Ada had 12 oranges. She gave 4 to her friend.
12 – 4 = 8
Example 3:
Uche counted 14 mangoes. He ate 5.
14 – 5 = 9
Example 4:
Amina had 10 sweets. She gave 2 to her brother.
10 – 2 = 8
Example 5:
There were 16 birds on a tree. 6 flew away.
16 – 6 = 10
Presentation Steps
- Step 1: Teacher revises the previous topic on addition.
- Step 2: Teacher introduces the new topic “Subtraction of Numbers.”
- Step 3: Teacher uses objects (sticks or bottle tops) to demonstrate subtraction.
- Step 4: Pupils use their own objects to practice subtraction.
- Step 5: Teacher explains subtraction with numbers on the board.
- Step 6: Pupils solve given exercises and share their answers.
Teacher’s Activities
- Demonstrate subtraction using real objects.
- Guide pupils in counting backward.
- Ask pupils to show subtraction using their materials.
- Encourage group and pair discussions.
- Provide correction and reinforcement.
Learners’ Activities
- Observe and listen to explanations.
- Use their materials to practice subtraction.
- Solve subtraction problems on the board.
- Participate in group activities.
- Explain how they got their answers.
Class Activity Discussion (FAQs with Answers)
- Q: What is subtraction?
A: Subtraction means taking away. - Q: What sign is used for subtraction?
A: The minus sign (–). - Q: What does the equals sign (=) show?
A: The total or what is left. - Q: What is 9 – 5?
A: 4 - Q: What is 12 – 3?
A: 9 - Q: What is 10 – 6?
A: 4 - Q: If 8 birds fly away from 15, how many remain?
A: 7 - Q: When you take 7 from 13, what is left?
A: 6 - Q: If you take away 9 from 18, what is left?
A: 9 - Q: Why do we subtract?
A: To know what remains after taking away.
Evaluation Questions
A. Fill-in-the-Blank (Choose a, b, c, or d)
- 6 – 1 = ___ (a) 4 (b) 5 (c) 6 (d) 7
- 9 – 5 = ___ (a) 4 (b) 3 (c) 5 (d) 6
- 11 – 5 = ___ (a) 6 (b) 7 (c) 8 (d) 9
- 12 – 3 = ___ (a) 10 (b) 9 (c) 8 (d) 7
- 14 – 3 = ___ (a) 12 (b) 11 (c) 13 (d) 10
- 16 – 7 = ___ (a) 9 (b) 8 (c) 7 (d) 10
- 18 – 9 = ___ (a) 8 (b) 9 (c) 10 (d) 11
- 10 – 6 = ___ (a) 4 (b) 3 (c) 5 (d) 6
- 19 – 8 = ___ (a) 12 (b) 11 (c) 10 (d) 9
- 13 – 7 = ___ (a) 5 (b) 6 (c) 7 (d) 8
B. Short Answer Questions
- What is subtraction?
- Write the sign used for subtraction.
- What is the result of 6 – 1?
- Subtract 5 from 9.
- Subtract 3 from 12.
- What is 14 – 3?
- What is 16 – 7?
- Take away 9 from 18.
- What is left when 8 is taken from 19?
- Take away 7 from 13.
Assessment
The teacher marks the pupils’ work, corrects mistakes, and praises good efforts.
Conclusion
The teacher concludes by saying:
“Subtraction means taking away. When you take away, you get what is left.”
Pupils repeat after the teacher:
“Subtraction means taking away!”