UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
Why, if two wrongs don't make a right, do two negatives make a positive in mathematics?
Question Date: 2015-04-19
Answer 1:

There is some math that you can do to convince yourself that multiplying 2 negative numbers gives a positive number. For example, let's say we want to evaluate -1 x (-2 +2). We know that the expression within the parentheses, -2 + 2, equals 0, so -1 x (-2 + 2) also equals 0. Using the distributive property, we know that -1 x (-2 + 2) = (-1 x -2) + (-1 x 2), which we know equals 0. The value of -1 x 2 is -2, because you simply add -1 two times. This means that (-1 x -2) must be equal to positive 2 in order for the whole expression to equal 0. This is just one of a few simple proofs you can use to show this idea.


Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2017 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use