Basic Operations

Grade 7 Math - Basic Operations

Lesson Objectives

Perform addition of large numbers accurately.
Carry out subtraction with regrouping where necessary.
Multiply multi-digit numbers efficiently.
Divide large numbers and interpret remainders.

Lesson Introduction

Basic operations — addition, subtraction, multiplication, and division — are the foundation of all mathematical problem-solving. Whether you're calculating money, distance, or time, mastering these operations is essential.

Core Lesson Content

Addition: Putting numbers together to find the total.

Subtraction: Taking one number away from another to find the difference.

Multiplication: Repeated addition of the same number.

Division: Splitting a number into equal parts.

Worked Examples

Example 1: Add

125,378 + 84,622

125,378 + 84,622 = 210,000

Explanation: Line up digits and add column by column.

Example 2: Subtract

205,000 - 86,435

205,000 - 86,435 = 118,565

Explanation: Regroup where necessary and subtract each digit column.

Example 3: Multiply

327 \times 46

327 \times 46 = 15,042

Explanation: Multiply step-by-step using long multiplication.

Example 4: Divide

9,856 \div 4

9,856 \div 4 = 2,464

Explanation: Use long division method to divide digit by digit.

Example 5: Add

678,945 + 223,711

678,945 + 223,711 = 902,656

Explanation: Start from rightmost digits and carry over where necessary.

Example 6: Subtract

1,000,000 - 456,789

1,000,000 - 456,789 = 543,211

Explanation: Make sure to borrow across zeros carefully.

Example 7: Multiply

123 \times 321

123 \times 321 = 39,483

Explanation: Multiply in parts: units, tens, hundreds, then sum.

Example 8: Divide

10,000 \div 25

10,000 \div 25 = 400

Explanation: Estimate and divide step-by-step or simplify using factors.

Example 9: Add

345,000 + 56,789

345,000 + 56,789 = 401,789

Explanation: Ensure digits are properly aligned before adding.

Example 10: Divide

2,375 \div 6

2,375 \div 6 = 395 \text{ remainder } 5

Explanation: Use long division; remainder may be expressed as fraction or decimal.

Exercises

Find $542,123 + 328,987$
Subtract $600,000 - 415,369$
[JAMB] Multiply $245 \times 38$ [Past Question]
Divide $12,456 \div 4$
[WAEC] Find $789,654 + 110,111$ [Past Question]
Subtract $999,999 - 654,321$
Multiply $89 \times 67$
[NECO] Divide $7,218 \div 9$ [Past Question]
What is $111,111 + 222,222$ ?
Evaluate $84,000 - 29,999$
Multiply $305 \times 55$
[NABTEC] Divide $14,382 \div 3$ [Past Question]
What is $999 \times 101$ ?
Subtract $800,000 - 123,456$
Divide $3,000 \div 12$

Conclusion/Recap

Today, we reviewed how to confidently work with large numbers using basic operations. Being accurate with these operations lays the groundwork for solving more advanced math problems. In our next lesson, we’ll explore Fractions and Decimals.