Absolute Value Sign
Date: 07/08/2003 at 12:23:56 From: Nick Subject: I need help in evaluating an absolute expression I understand how an absolute value works but when combined with order of operation and signs I get confused. Please help me out if you can. -|8-3|+|3+(-8)| -|8-3|+|3+(-8)| =5+5 =10
Date: 07/08/2003 at 13:00:36 From: Doctor Peterson Subject: Re: I need help in evaluating an absolute expression Hi, Nick. The key is to take one step at a time, working from the inside out. An expression like -|5| means that you FIRST find the absolute value of 5, and THEN negate that. That's because the - operator has to work on a number, and to get that number you have to evaluate |5| first. Your only error is that -|8-3| is negative, not positive, since 8-3 evaluates to 5, and |5| is 5, and its negative is -5. Incidentally, you can think of the absolute value sign as both an operation and a grouping symbol: it functions as parentheses, forcing you to evaluate what's inside first; then it does its own work; and then the result can be used by operations outside. If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
Date: 07/08/2003 at 14:23:01 From: Nick Subject: Thank you (I need help in evaluating an absolute expression) Just a short note saying thank you....I knew there was something simple I was missing!
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.