Subtraction of 2-Digit Numbers Mathematics Primary 2 Second Term Lesson Notes Week 3

Subject: Mathematics
Class: Primary 2
Term: Second Term
Week: 3
Age: 7-8 years
Topic: Subtraction of Two 2-Digit Numbers with Regrouping
Sub-topic: Subtraction of 2-Digit Numbers
Duration: 40 minutes

Behavioural Objectives:

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

• Count numbers from 490 to 510 and 1 to 510.
• Write numbers from 490 to 510 and 1 to 510 in numerals and words.
• Subtract two 2-digit numbers with regrouping.
• Solve subtraction problems involving real-life situations, such as calculating reduction in stock (e.g., foodstuff in a store).
• Use number flashcards to tell subtraction stories and solve them.
• Sing subtraction songs to reinforce the concept of subtraction.

Keywords:

• Subtraction
• Regrouping
• 2-digit numbers
• Counting
• Writing numbers
• Flashcards
• Real-life problems

Set Induction:

Start the lesson by talking about a scenario in a kitchen store where items (e.g., bags of rice) are sold and need to be subtracted from the stock. Show how subtraction helps in tracking what is remaining. Use a number chart (490-510) to encourage counting from 490 to 510.

Entry Behaviour:

Pupils should already have a basic understanding of simple subtraction and counting numbers up to 100.

Learning Resources and Materials:

• Flashcards for subtraction problems
• Number chart (490-510)
• Subtraction songs
• Beads or counters for hands-on activities
• Chalkboard/whiteboard for solving problems

Building Background/Connection to Prior Knowledge:

Pupils will recall the addition and subtraction skills from previous lessons. This lesson will build on their understanding of subtraction by introducing regrouping.

Embedded Core Skills:

• Problem-solving
• Communication and collaboration
• Digital literacy
• Creativity and imagination
• Leadership and personal development

Learning Materials:

• Flashcards
• Number chart (490-510)
• Beads or counters
• Subtraction songs

Reference Books:

• Lagos State Scheme of Work
• Primary Mathematics Textbook for Primary Schools

Instructional Materials:

• Flashcards
• Number chart
• Chalkboard/whiteboard

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Content:

1. Counting Numbers (490-510 and 1-510):

• Count numbers from 490 to 510 and 1 to 510.
• Write numbers 490 to 510 and 1 to 510 in numerals and words.
  Example:
  490 = Four hundred and ninety
  510 = Five hundred and ten

2. Subtraction of Two 2-Digit Numbers with Regrouping:

• Teach how to subtract two 2-digit numbers with regrouping by borrowing from the next higher place value (e.g., tens place).
  Example:
  47 – 25 = 22
  Explanation:
  7 – 5 = 2 (ones place)
  4 – 2 = 2 (tens place)

3. Real-Life Application of Subtraction:

• Discuss real-life situations like reducing stock in a store. For example, if there are 50 bags of rice and 20 bags are sold, how many are left?
  50 – 20 = 30

4. Hands-On Activities:

• Pupils in small groups use number flashcards to tell subtraction stories and solve them.
• Use beads or counters to demonstrate the subtraction process with regrouping.

5. Subtraction Songs:

• Teach the pupils a subtraction song to help them remember how to perform subtraction with regrouping.

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Evaluation Questions (15 fill-in-the-blank questions):

1. The number that comes after 490 is __________.
   a) 491
   b) 500
   c) 510
   d) 470
2. 47 – 25 = __________.
   a) 22
   b) 23
   c) 21
   d) 20
3. What is 75 – 34?
   a) 41
   b) 42
   c) 40
   d) 39
4. The expanded form of 510 is __________.
   a) 500 + 10
   b) 500 + 1
   c) 400 + 10
   d) 510
5. 50 – 23 = __________.
   a) 27
   b) 28
   c) 29
   d) 30
6. The number that comes before 510 is __________.
   a) 509
   b) 500
   c) 490
   d) 495
7. What is 69 – 42?
   a) 27
   b) 25
   c) 26
   d) 28
8. 54 – 28 = __________.
   a) 26
   b) 25
   c) 27
   d) 24
9. The expanded form of 490 is __________.
   a) 400 + 90
   b) 500 + 10
   c) 400 + 50
   d) 490
10. What is 84 – 47?
    a) 37
    b) 38
    c) 39
    d) 36
11. 90 – 55 = __________.
    a) 35
    b) 34
    c) 36
    d) 33
12. What is the sum of 75 and 24?
    a) 99
    b) 100
    c) 101
    d) 102
13. 100 – 65 = __________.
    a) 35
    b) 36
    c) 34
    d) 33
14. 68 – 21 = __________.
    a) 47
    b) 46
    c) 48
    d) 45
15. The number before 500 is __________.
    a) 499
    b) 400
    c) 450
    d) 470

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Class Activity Discussion (15 FAQs with answers):

1. What does regrouping in subtraction mean?
   It means borrowing from the next higher place value (e.g., tens) when the number in the ones place is smaller than the number we are subtracting.
2. How do we subtract with regrouping?
   We borrow from the next place value to make the subtraction easier. Example: 47 – 25, we borrow 1 from the tens to subtract.
3. What is subtraction in real life?
   Subtraction helps us find out how much is left, like how much food is left in the kitchen after some has been used.
4. How can I practice subtraction at home?
   You can use everyday items like fruits or toys to subtract. For example, if you have 10 apples and eat 3, how many are left?
5. Why do we need to know subtraction?
   Subtraction helps us solve problems like counting money, keeping track of stock, and understanding changes in numbers.
6. How do we know when to borrow in subtraction?
   We borrow when the number in the ones place of the top number is smaller than the bottom number.
7. What is 100 – 25?
   The answer is 75.
8. What happens if we don’t borrow in subtraction?
   We may end up with the wrong answer if we don’t borrow when needed.
9. Can we subtract numbers without regrouping?
   Yes, if the number in the top digit is larger than the bottom digit, no borrowing is needed.
10. How do we make subtraction easier?
    We practice subtraction with simple examples and use real-life objects to make it clearer.
11. What is the expanded form of 510?
    It is 500 + 10.
12. How can we use subtraction songs?
    Songs help us remember how to subtract and make learning fun.
13. What is a subtraction story?
    A subtraction story is when we use real-life situations, like shopping, to explain subtraction.
14. Can subtraction help us in shopping?
    Yes, it helps us calculate how much we have left after buying something.
15. How do we use subtraction in school?
    We use it to subtract marks from a total score or count the number of items in a class.

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Teacher’s Activities:

1. Revise the numbers 490 to 510 with the pupils.
2. Demonstrate subtraction of two 2-digit numbers with regrouping using simple examples on the board.
3. Show how to relate subtraction to real-life situations (e.g., subtraction of stock in a store).
4. Engage pupils in subtraction stories using flashcards.
5. Lead a class-wide singing of a subtraction song to reinforce the concept.

Learners’ Activities:

1. Count from 490 to 510 and 1 to 510 aloud.
2. Write the numbers 490 to 510 and 1 to 510 in numerals and words.
3. Subtract two 2-digit numbers with regrouping using chalkboards or worksheets.
4. Participate in group activities using flashcards and telling subtraction stories.
5. Sing the subtraction song as a class.

Assessment:

1. Solve 53 – 25.
2. Write the number 510 in words.
3. Subtract 46 from 72.
4. What is the expanded form of 490?
5. Subtract 23 from 61.
6. Solve: 85 – 47.
7. What is 90 – 34?
8. Subtract 18 from 52.
9. What is 100 – 66?
10. Write a subtraction story and solve it.

Conclusion:

The teacher will review the subtraction problems with the students, providing feedback and ensuring understanding of subtraction with regrouping. They will reinforce the real-life applications and encourage further practice.