Revision of First Term’s Work — Counting, Ordering and Adding Numbers – Primary 1 Basic Science Lesson Note

TOPIC: Revision of First Term’s Work
SUBTOPIC: Counting and Writing Numbers 1–70; Ordering Numbers 21–50; Addition of 1-Digit Numbers; Value of Zero
CLASS: Primary 1
DATE: ____________________
PERIOD: ____________________
DURATION: 40 minutes

LEARNING OBJECTIVES

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

1. Count and write numbers from 1 to 70 correctly.
2. Order numbers 21–50 in ascending and descending order.
3. Add two one-digit numbers with sum not more than 10.
4. Explain the value of zero (0) in numbers.

KEY VOCABULARY WORDS

Count, Number, Add, Plus (+), Equal (=), Zero (0), More than, Less than, Order, Ascending, Descending.

INSTRUCTIONAL MATERIALS

• Number chart (1–70)
• Flashcards with numbers 1–70
• Bottle tops or counters for counting
• Abacus or sticks
• Chart showing “Value of Zero”
• Marker and board

INTRODUCTORY ACTIVITY

The teacher shows the pupils a number chart (1–70) and asks:

• “Who can count from 1 to 20?”
• “What comes after 19?”
• “What number comes before 50?”

Pupils take turns to count aloud.
The teacher writes random numbers (e.g., 25, 31, 44, 10) on the board and asks pupils to identify and say each number aloud.

CONTENT OF THE LESSON

1. Counting and Writing Numbers (1–70)

Numbers are used to show how many things we have.
We can count numbers in order as shown below:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10,

11, 12, 13, 14, 15, 16, 17, 18, 19, 20,

21, 22, 23, 24, 25, 26, 27, 28, 29, 30,

31, 32, 33, 34, 35, 36, 37, 38, 39, 40,

41, 42, 43, 44, 45, 46, 47, 48, 49, 50,

51, 52, 53, 54, 55, 56, 57, 58, 59, 60,

61, 62, 63, 64, 65, 66, 67, 68, 69, 70

🧮 Diagram: Number Chart (1–70)

Pupils can practice writing numbers 1–70 neatly in their exercise books.

2. Ordering Numbers 21–50

To order numbers means to arrange them in sequence.

• Ascending order means from smallest to largest (e.g., 21, 22, 23, 24).
• Descending order means from largest to smallest (e.g., 50, 49, 48, 47).

3. Addition of Two 1-Digit Numbers (Sum ≤ 10)

Addition means putting things together.
We use the plus sign (+) and equal sign (=) in addition.

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

Illustration using objects:

🧩 Try these:
1 + 1 = 2
3 + 2 = 5
4 + 4 = 8
5 + 3 = 8

4. The Value of Zero (0)

Zero (0) means nothing or no object.

Example:
If you have 5 sweets and you eat all the 5 sweets; you have 0 sweets left.

🍬🍬🍬🍬🍬 − 🍬🍬🍬🍬🍬 = 0

Zero helps us to write large numbers like 10, 20, 100, etc.
In 10, zero shows there are no units.

CLASS EXERCISE 1

Write the following numbers in words:

1. 15
2. 29
3. 37
4. 48
5. 60

CLASS EXERCISE 2

Fill in the missing numbers:

1. 21, ___, 23, ___, 25
2. 46, 47, ___, 49, ___
3. 5 + 2 = ___
4. 3 + 3 = ___
5. 0 means ___________

CLASS EXERCISE 3

Arrange the numbers below in:
(a) Ascending order: 25, 20, 30, 15, 10
(b) Descending order: 42, 47, 45, 49, 40

ASSIGNMENT (Multiple-Choice Questions)

(Write answers in your exercise book)

1. Which number comes after 19? (a) 18 (b) 20 (c) 21 (d) 10
2. 3 + 4 = ______ (a) 8 (b) 6 (c) 7 (d) 9
3. Zero means ______ (a) nothing (b) ten (c) one (d) something
4. Arrange in ascending order: 31, 33, 30, 32 → (a) 30, 31, 32, 33 (b) 33, 32, 31, 30 (c) 31, 30, 33, 32 (d) none
5. Which number is smaller? 25 or 29 → (a) 29 (b) 25 (c) both (d) none