Multiplying/Dividing Integers

Multiplying and Dividing Integers

Learning Targets

I can multiply and divide integers based on the number system.

What Can You Do To Multiply Integers?

• Make an educated guess based on the question

• Discuss with the class on why you think your answer is correct

• Brainstorm of the possible answer gained from discussion

Multiplying Integers Basics

• Multiplying integers is like a tennis rally. For example:

• 5 ⋅ -1 = -5

• -5 ⋅ -1 = 5

• 5 ⋅ -1 = -5

• The switch works either way, and the process loops forever.

Multiplying by Multiple Negative Integers

You can also multiply multiple integers, and it works the same way. For example, 2(-1)(-1)(-1) is -2.

What Can You Do To Divide Integers?

• Use knowledge from the previous slides to gather possible information

• Discuss with the class on why you think your answer is correct

• Brainstorm of the possible answer gained from discussion

Dividing Integers Basics

• Dividing integers works the same way as multiplying integers, since they are basically the same operation and method. For example:

• 12 ÷ 6 = 2

• 12 ÷ -6 = -2

• -12 ÷ -6 = 2

Odd/Even Factors

• An odd factor of negative integers will result in a positive answer.

• An even factor of negative integers will result in a negative answer.

• Three is an odd number, so three negatives in a math problem will result in a positive answer.

• 102 is an even number, so 102 negatives in a math problem will result in a negative answer.

All Together Now!

• Multiplying and dividing integers at the same time is possible. Here's how to solve them:

• Cancel out the common factors (if there is any).

• Use the skills needed to solve the problem.

• DO NOT guess the answer.

• Instead, do the math and solve the problem. Check your work.

Practice

Let's try doing the math together!

Multiple Choice

21 * -13 = ?

• -204

• 204

• -273

• 273

Multiple Choice

-45 * -74 = ?

• -3,330

• 3,330

• 4,660

• -1,336

Multiple Choice

12 * -22 = ?

• 236

• -249

• 264

• -264

Multiple Choice

-4 / 31 = ?

• 1.5

• -0.1111111111...

• 0.13234

• -0.129032258065

Multiple Choice

-41 / -20 = ?

• 2.05

• 1.07

• -2.14

• -1.07

Now that you know how to multiply and divide integers...

Have a nice lesson!