Eli5 Why is a negative times a negative a positive?

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I’m thinking of it like money. If I owe 5.00 dollars and then a multiply my debt by 5 dollars, I should be in debt by 25 dollars right? But -5 time -5 is 25. Please help.

Edit: my example was wrong sorry.

Edit: I’m still so confused but I think I got it. If I owe someone a dollar (-1). But that person doesn’t exist (-1). Id have my dollar still. Is that right?

In: Mathematics

12 Answers

Anonymous 0 Comments

Think of numbers as a line. Positive numbers go off to the right, negative numbers go off to the left. Multiplying a positive number by -1 (for example) means that you turn around and go to the left.

Multiplying a negative number by another negative is like taking someone going left and telling them to turn around and go in the other direction. So they go right. Back in the positive direction.

Anonymous 0 Comments

Counting only works with natural numbers. Negative numbers are different in this respect, you cannot count with those. Your idea with “debt” might only give you a short glimpse, but that isn’t a very accurate one.

Part of the reason why it to so long to discover them.