Addition (1–80) — Learning Math Facts and Skip Counting – Primary 1 Basic Science Lesson Note

TOPIC: Introduction to Math Facts – Addition (1–80)
SUBTOPIC: Counting Numbers 71–80, Understanding and Performing Addition, Real-Life Application, and Skip Counting in 2s and 3s
CLASS: Primary 1
DATE: ____________________
PERIOD: ____________________
DURATION: 40 minutes

LEARNING OBJECTIVES

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

1. Count and identify numbers from 71 to 80 correctly.
2. Explain the meaning of addition using everyday examples.
3. Add two or three 1-digit numbers with a total not more than 20.
4. Apply addition to real-life situations.
5. Skip count in 2s and 3s accurately.

KEY VOCABULARY WORDS

Add, Plus (+), Equal (=), Total, Altogether, Sum, Count, Skip Counting, Two’s, Three’s, Numbers.

INSTRUCTIONAL MATERIALS

• Number chart (1–100)
• Flashcards of numbers (71–80)
• Bottle tops or counters
• Abacus or sticks
• Pictures of fruits or toys for counting
• Chart showing skip counting in 2s and 3s
• Whiteboard and markers

INTRODUCTORY ACTIVITY

1. The teacher writes numbers 71–80 on the board and asks pupils to read aloud after her/him.
2. Pupils practice counting forward and backward between 71 and 80.
3. The teacher then draws two groups of objects (e.g., apples) on the board and asks, “How many apples do we have altogether?” This leads to the introduction of addition.

CONTENT OF THE LESSON

1. Counting Numbers (71–80)

Counting continues from where we stopped last week. Let’s read the numbers from 71 to 80:

71, 72, 73, 74, 75, 76, 77, 78, 79, 80

🧮 Diagram: Number Chart (71–80)

2. Meaning of Addition

Addition means putting things together to get the total.
We use the plus sign (+) and equal sign (=) to show addition.

Example 1:
2 + 3 = 5 → “Two plus three equals five.”

Example 2 (using objects):

Addition helps us to find how many in all or how many altogether.

3. Adding Two or Three 1-Digit Numbers (Sum ≤ 20)

We can add two or three small numbers easily:

🧮 Diagram: Simple Addition Illustration

🍎🍎 + 🍎🍎🍎 = 🍎🍎🍎🍎🍎

(2 + 3 = 5)

4. Real-Life Application of Addition

Addition happens every day in real life.

• If you have 3 pencils and your friend gives you 2 more, you now have 5 pencils.
• If there are 4 boys and 3 girls in a class, there are 7 children altogether.

5. Skip Counting in 2s and 3s

Skip counting means counting by jumping numbers.

• In 2s: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20
• In 3s: 3, 6, 9, 12, 15, 18

🧩 Diagram: Skip Counting on Number Line

CLASS EXERCISE 1

1. Count and write the numbers from 71 to 80.
2. Write the missing numbers: 71, ___, 73, ___, 75, ___, 77, ___, 79, ___
3. 2 + 3 = _______
4. 4 + 5 + 1 = _______
5. 5 + 3 = _______

CLASS EXERCISE 2

1. There are 6 oranges in one basket and 4 oranges in another basket.
   • How many oranges altogether?
2. If you have 3 sweets and your friend gives you 2 more, how many sweets do you now have?
3. Write the next three numbers when skip counting by 2s: 2, 4, 6, ___, ___, ___
4. Write the next three numbers when skip counting by 3s: 3, 6, 9, ___, ___, ___
5. Complete: 7 + 2 = ______

CLASS EXERCISE 3 (Optional Enrichment for Fast Learners)

ASSIGNMENT (Multiple-Choice Questions)

(Write answers in your exercise book)

1. 2 + 3 = ______ (a) 6 (b) 4 (c) 5 (d) 7
2. The sign used for addition is ______ (a) – (b) + (c) × (d) ÷
3. Counting in 2s means saying ______ (a) 1, 2, 3 (b) 2, 4, 6 (c) 1, 3, 5 (d) 2, 3, 4
4. 5 + 2 + 3 = ______ (a) 9 (b) 10 (c) 8 (d) 11
5. Which number comes after 79? (a) 78 (b) 80 (c) 81 (d) 82