David T. answered 08/23/13
MS Chemistry with 7+ Years Teaching/Tutoring Experience
Hello, Mary. The first step in this sort of problem is to understand what the current order of operations (PEMDAS - Parenthesis, Exponents, Multiplication, Division, Addition, and Subtraction - in that order) is. So here we see that the first thing (as it is currently written) would be the division - followed by addition and subtraction. To change the first thing to be the addition (as your problem states) you simply add parenthesis around the terms to be added.
(3+4)/2-7 And now the addition is first. Next step is to make subtraction happen before division. This can be done by another set of parenthesis.
(3+4)/(2-7) Now we see that the order of operations (again using the PEMDAS rule) is addition, then subtraction, followed by division. Just as your problem asks for (+,-,/). I hope that helps you understand order of operations a bit more.
-David
Mary A.
I get it now! I knew I had to add the first set of parentheses but did not understand the second set. I am 50 years away from high school algebra and have forgotten much.. Thank you for a quick reply Mary
08/23/13