Nigeria - Primary 2 - General Mathematics - Subtraction

Nigeria - Primary 2 - General Mathematics - Subtraction

Lessonotes Nigeria curriculum lesson video for Primary 2 General Mathematics. This lesson focuses on Subtraction for classroom teaching, revision, and home learning.

Country: Nigeria
Grade: Primary 2
Subject: General Mathematics
Scheme: Lessonotes Curriculum
Theme: Basic Operations
Period: Term 1
Week: 4

Performance Objectives
1. subtract 2-digit numbers with out exchanging or renaming;
2. subtract 2-digit numbers with exchanging and renaming;
3. apply addition and subtraction in everyday activities.

Lesson Content
Grade / Level: Primary 2
Subject: General Mathematics
Theme: Basic Operations
Topic: Subtraction
Term: 1st Term
Week: 4

---

1. **Overview and Learning Objectives**

This topic focuses on the fundamental operation of subtraction, building upon learners' prior knowledge of numbers and single-digit subtraction. Subtraction is a critical skill for daily life, enabling individuals to determine remaining quantities, calculate differences, and manage resources effectively. Understanding subtraction is essential for practical activities such as managing money, sharing items, calculating stock, and understanding changes in quantities.

Upon completion of this lesson, students will be able to:
* Subtract two-digit numbers without needing to exchange or rename (i.e., without "borrowing").
* Subtract two-digit numbers by exchanging or renaming (i.e., "borrowing") from the tens place.
* Identify and describe various real-life situations where the concepts of addition and subtraction are applied.

This knowledge is crucial for everyday activities in Nigeria, such as accurately giving or receiving change in markets, managing small allowances, determining how many items are left after some have been used or sold, and calculating differences in quantities of goods or people within their communities.

2. **Key Concepts and Explanations**

**2.1. Definition of Subtraction**
Subtraction is one of the four basic arithmetic operations. It involves taking away one number from another, finding the difference between two numbers, or determining how much is left after a portion has been removed.
* **Minuend:** The number from which another number is subtracted (the larger number).
* **Subtrahend:** The number being subtracted (the smaller number).
* **Difference:** The result obtained after subtracting the subtrahend from the minuend.
* The symbol for subtraction is the minus sign (-).

**2.2. Place Value Review**
Before performing two-digit subtraction, students must have a solid understanding of place value (Units and Tens).
* **Units (U):** Represents single items (0-9).
* **Tens (T):** Represents groups of ten (e.g., 1 ten = 10 units, 2 tens = 20 units).
When subtracting two-digit numbers, numbers are arranged vertically, aligning the units digits and tens digits. Subtraction always begins from the units column, moving to the tens column.

**2.3. Subtraction of 2-Digit Numbers without Exchanging/Renaming**
This type of subtraction occurs when the units digit of the minuend is greater than or equal to the units digit of the subtrahend, and similarly for the tens digits. No "borrowing" is required.

**Step-by-step Example 1: `45 - 23`**
* **Context:** A hawker had 45 oranges and sold 23 of them. How many oranges are left?
* **Step 1: Arrange the numbers vertically, aligning by place value.**
```
T U
4 5 (Minuend)
- 2 3 (Subtrahend)
-----
```
* **Step 2: Subtract the units digits.**
* Subtract 3 units from 5 units: 5 - 3 = 2 units.
* Write 2 in the units column of the answer.
```
T U
4 5
- 2 3
-----
2
```
* **Step 3: Subtract the tens digits.**
* Subtract 2 tens from 4 tens: 4 - 2 = 2 tens.
* Write 2 in the tens column of the answer.
```
T U
4 5
- 2 3
-----
2 2
```
* **Result:** 22 oranges are left.

**2.4. Subtraction of 2-Digit Numbers with Exchanging/Renaming ("Borrowing")**
This type of subtraction is required when a digit in the minuend is smaller than the corresponding digit in the subtrahend, starting from the units column. In such cases, one 'ten' is exchanged from the tens column of the minuend and converted into 'ten units', which are then added to the units column of the minuend.

**Step-by-step Example 2: `52 - 27`**
* **Context:** A baker prepared 52 loaves of bread. By afternoon, 27 loaves were sold. How many loaves are remaining?
* **Step 1: Arrange the numbers vertically, aligning by place value.**
```
T U
5 2 (Minuend)
- 2 7 (Subtrahend)
-----
```
* **Step 2: Subtract the units digits.**
* Try to subtract 7 units from 2 units (2 - 7). This is not possible in basic subtraction as 2 is smaller than 7.
* **Step 3: Exchange/Rename (Borrow) from the tens column.**
* Go to the tens column of the minuend (which has 5 tens).
* Take 1 ten from the 5 tens, leaving 4 tens. Cross out 5 and write 4 above it.
* Convert the borrowed 1 ten into 10 units. Add these 10 units to the existing 2 uni

Видео Nigeria - Primary 2 - General Mathematics - Subtraction канала Lessonotes Video Teachings