Dear Sensei Math:
I was trying to help Peter with his homework earlier today, and he kept getting mixed up on his multiplying positive and negative numbers. I told him it's been so long since I've done that, the dinosaurs were still roaming the Earth! I was wondering if maybe you could give him a hand.
Yours truly,
Alice Nelson
Well, Alice, I think I can help you. The good news is that it's way easier to multiply and divide integers than it is to add and subtract them.
First off, you're going to need to meet a few friends of mine.
First off, let's start off with the positives. Positive Pete and Positive Patty are obviously going to make a great couple. Therefore, they are going to have a positive relationship.
Now, let's say Negative Ned tried to start a relationship with Positive Patty. It's not going to work out very well. Patty, the eternal optimist, is going to really irritate Negative Ned, who always finds a problem with everything.
And let's face it, it's not going to work out for Positive Pete and Negative Nancy either.
Same with the numbers. They're going to come out negative when you multiply a negative by a positive, and vice versa.
However, perhaps surprisingly, Negative Ned and Negative Nancy both get along wonderfully. They both hate everything, and therefore, they hate everything together. They get along so well. They have a positive relationship.
It works out the same way with numbers. Multiply a negative by another negative, and you get a positive number! It's so weird, but it's true!
One day I will write a post about why this is true, but this is one where you don't have to understand why, because the mathematical rule is so easy to remember.
I hope this helps, Alice!
No comments:
Post a Comment