Teacher2Teacher

Q&A #4120

Teachers' Lounge Discussion: Interviewing questions

T2T || FAQ || Ask T2T || Teachers' Lounge || Browse || Search || T2T Associates || About T2T

View entire discussion
[<< prev] [ next >>]

From: quantgal

To: Teacher2Teacher Public Discussion
Date: 2009062911:59:55
Subject: Re: mathematics

Assuming your question is sincere, here is a response: Because you are taking the opposite of the absolute value of the product two times. The first time (minus times plus) you multiply a negative times the absolute value product , you will yield a negative answer. The second negative makes that product positive, when you take the opposite the second time. Example: -2 x -3 = (-1 X 2) x (-1 x 3) rearrange: (2 x 3) x (-1) x (-1) 2 x 3 = +6 Substitute and multiply by the first negative: (+6) x (-1) = -6 Substitute and multiply by the second negative: (-6) x (-1) = the opposite of negative 6, which is +6. Therefore, minus times minus is plus.

Post a reply to this message
Post a related public discussion message
Ask Teacher2Teacher a new question


[Privacy Policy] [Terms of Use]

_____________________________________
Math Forum Home || The Math Library || Quick Reference || Math Forum Search
_____________________________________

Teacher2Teacher - T2T ®
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/