Multiplying Positive and Negative Integers

A Negative Times A Positive is Negative

When it came to deciphering negative and positive integers, the bottom line from my student days was always, "Remember the rule." This can be helpful when problem solving but understanding is always better.

Let's think about a negative number multiplied by a positive number. The rule is that a negative times a positive is negative. Great, but what exactly does this mean? Did anyone watch the Super Bowl? Okay, maybe that's a dumb question, but here is a way to use the Super Bowl as an example of multiplying negative and positive numbers.

Supposed you bet your friend $5 that San Francisco would win the Super Bowl. Guess what? You lost that bet, but since you bet one friend $5, that's all you lost. 

1 X $5 = $5

or since you are losing $5 call it,

1 X (-5) = -5

Had you made this bad bet with three friends, you'd be out three times the amount because . . .

3 X (-5) = -15

A Negative Times a Negative is Positive

But what if you won that bet? In that case, you are taking away the possibility of losing $5, so . . .

(-3) X (-5) = 15

-3 is the amount of times you could have paid a bad bet if you made one, 
while -5 represents the amount you could have lost.

Therefore, congrats! You made $15!
This worksheet is part of my Positive and Negative Integers Bundle. Sorry but, $5 is a little more than you would need to pay to buy this resource. Not a bad price for all that you get!

Next time you want to teach that a negative times a positive is a negative, try explaining this to your kids It's certainly better than telling them to just memorize the rules.

       Positive and Negative Integer Operations with Word Problems

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See you next week when we look at ways to make the classroom a kinder place.

Monday Music Moves Me

This week's theme is songs with names in the title, so I'm starting with a song by Kiss that is dramatically different from any other song this band has ever written, "Beth."

My next song was sung at the first concert I ever attended at Red Rocks in Colorado. I've always loved, "Amie" by Pure Prairie League!

Finally, this is an old song that we always sang to our daughter, Judy. Plus, it is totally goofy! Please listen to "Judy in Disguise" by John Fred and His Playboy Band.