Multiplication of Integers

Introduction

In this lesson, we will review the multiplication of integers. In order to multiply integers you must know the following key points:

Key Points:

• Integers are distributed in 2 categories: positives and negatives
• Integers are whole numbers
• Zero is neither a positive or negative number
• If the signs are the same the product will be positive
• If the signs are different the product will be negative 

 Figure 1 Multiplication of Integers Number Line

Multiplication of Integers

Let's say that we have the following problem:

4 x -8

From the above key points, we know that if the signs are different, then the product will be negative.
In this case we have positive 4 (+4) and negative 8 (-8). Since the signs are different we know that the product will be negative. Now just simply multiply 4 x 8 and we get a product of 32. Remember to add the negative sign to get your final product of -32.

4 x -8 = -32