Mixed Operations

Date: 04/08/97 at 04:40:22
From: River House Publications
Subject: Mixed Operations

I have been working on the following problem:
839 - 319 + 200 / 20 x 15 =

The answer I first got was 540.  However, I am not so sure because I 
cannot remember if I should have first multiplied the 20x15 before 
working out the rest of the sum. Could you tell me what I should have 
done if I was incorrect.  Thank you.

Mark

Date: 04/08/97 at 11:01:28
From: Doctor Mitteldorf
Subject: Re: Mixed Operations

Dear Mark,

Whoever gave you this problem could have been clearer, it's true.  
But there is a rule that if they're not telling you what order to do 
the operations in then, you just do parentheses, exponents, 
multiplication-division, then addition-subtraction. So in the absence 
of any other instructions I'd just go from left to right, for the 
multiplication/division:

200 / 20 = 10
10 * 15 = 150

839 - 319 + 150 = 670

-Doctor Mitteldorf,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/