Math Lesson Plan · Grades 5–8

Multiplying Positive and Negative Numbers Lesson

Teach students to multiply positive and negative integers with this four-page lesson plan and worksheet. Two sign rules govern all integer multiplication: same signs produce a positive result, and different signs produce a negative result. Students practice 25 multiplication problems ranging from two-factor to multi-factor expressions. Full answer key included.

Lesson Overview

Multiplying Positive and Negative Numbers

Integer multiplication follows two simple sign rules. When the signs of both factors are the same (both positive or both negative), the product is positive: (−3) × (−4) = 12 and 3 × 4 = 12. When the signs differ, the product is negative: (−3) × 4 = −12.

For expressions with more than two factors, apply the rules one pair at a time. Count the number of negative factors: an even count gives a positive result, an odd count gives a negative result. The lesson builds this understanding with worked examples before students complete the worksheet.

The worksheet has 25 problems, ranging from simple two-factor pairs to longer multi-factor products. Students must apply the sign rules accurately to reach the correct result. A complete answer key is on page 4.

How to Use This Lesson

1. Present the two sign rules on pages 1–2: same signs = positive, different signs = negative. Work through several examples with students.

2. Extend to multi-factor expressions: demonstrate counting negative factors to predict the sign before multiplying.

3. Distribute the worksheet (pages 3–4). Complete all 25 problems, then review answers using the answer key on page 4.

Printable Resource

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