How to Multiply or Divide Integers

Being able to multiply and divide positive and negative numbers correctly is one of those basic skills that, once you have the hang of it, will make it easier for you to learn later skills in your algebra class.. This tutorial will teach you how to multiply or divide integers when the signs of the numbers are the same and when the signs are different.

Instructions

1. To multiply integers with like signs, multiply the numbers and put a positive sign in front of the answer, regardless of whether the numbers were both positive or both negative.

   Imagine you're going on a trip with three friends and you want to split the cost evenly. The trip costs $200, so each person will have to contribute $50.

2. To divide integers with like signs, divide the numbers and put a positive sign in front of the answer, regardless of whether the numbers were both positive or both negative.

   There is no good way to model this one. You just have to accept that it works out this way.

3. 

   To multiply integers with unlike signs, multiply the numbers and put a negative sign in front of the answer. This is different from adding or subtracting signed integers because it doesn't matter which number is larger.

   For example, if three people each buy a $2 fruit smoothie, then they'll owe the cashier $6.

4. 

   To divide integers with unlike signs, divide the numbers and put a negative sign in front of the answer. This is also different from adding or subtracting signed integers because it still doesn't matter which number is larger.

   Six friends go in together on something that costs $18. If they split it evenly, each person will owe $3.

Tips & Warnings

• This also applies to fractions, decimals, and other numbers you may be working with.

• Make sure you are using the right process. If you are multiplying or dividing integers with the same sign, the answer is always positive. If you are multiplying or dividing integers with different signs, the answer is always negative.

Resources

• Multiplying and Dividing Integers
• Dead Bunny's Guide to Multiplying and Dividing Integers