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Common PEMDAS Errors


Date: 12/28/2001 at 12:05:31
From: Unknown
Subject: PEMDAS

What does PEMDAS mean?


Date: 12/28/2001 at 13:56:43
From: Doctor Tim
Subject: Re: PEMDAS

It's a way of remembering the order of operations:

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction

Many of us are wary of such memory devices, however. I have seen many 
students get it wrong while reciting "PEMDAS" to themselves, for 
example, by failing to recognize implied multiplication, or, when they 
do algebra, assuming that if there is a variable, it means they "can't 
do it" so they move on. For example:

3 + 4x

The student said, "I don't know x, so I can't do the multiplication. 
So I go on to addition, and that's 3 + 4, so I get 7x."

- Doctor Tim, The Math Forum
  http://mathforum.org/dr.math/   
    
Associated Topics:
Elementary Multiplication
Middle School Algebra

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