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Introduction to :

You've made it past addition and subtraction. Guess what's next? It's time to learn the ropes of multiplying and dividing positives and negatives.

The rules for multiplication and division are exactly the same: multiply and divide the numbers as normal. If the signs are the same the answer is positive. If the signs are different, the answer is negative.


Positive(x) or (÷)positive=positive
Positive(x) or (÷)negative=negative
Negative(x) or (÷)positive=negative
Negative(x) or (÷)negative=positive

Yep, two wrongs (negatives) actually do make a right (positive). 

Walk this Way

Here is one way to visualize this: if you take a video of someone walking backward (a negative), then play the video in reverse (another negative), the person will be walking forward (in the positive direction).

Batman and the Joker

Think of someone you consider to be a good guy (like Batman) and someone who is a bad guy (like the Joker). Next, ask these questions:

  1. If something good (+) happens to someone good (+): is that good or bad, like Batman winning the lottery? 
    • Good (+)
  2. If something good (+) happens to someone bad (-): is that good or bad, like the Joker winning the lottery? 
    • Bad (-)
  3. If something bad (-) happens to someone good (+): is that good or bad, like Batman being captured?
    • Bad (-)
  4. If something bad (-) happens to someone bad (-): is that good or bad, like the Joker being captured? 
    • Good (+)

Multiplying and Dividing Integers Example

ProblemSigns same or different?Answer
(-7) x (-8)Same+56
120/(-12)Different-10
(-13) x 2Different-26
98/2Same+49

Look Out: after students learn the rules for multiplication and division, they often want to apply these rules to addition as well. Be careful, they only work for multiplication and division.


Multiplying and Dividing Integers Exercise 1

125/(-5)

Multiplying and Dividing Integers Exercise 2

(-49)/(-7)

Multiplying and Dividing Integers Exercise 3

(-14) x 4

Multiplying and Dividing Integers Exercise 4

(-20) x (-5) / (-25)

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