# Thread: Having trouble with order of operations with fractions

1. ## Having trouble with order of operations with fractions

Hello all. I am a newbie here and could really use some help with a math problem. I searched the boards and did not see anything similar so here goes...

The problems is:

Evaluate 2 – 20 ÷ (1/3 + 1/4) x 7

Now I understand the basic order of operations but these added fractions are throwing me off. I made an attempt at the problem by adding the fractions which came to 7/12 which I then turned into a decimal but I know that can't be right. If someone could explain this to me, I would really appreciate it and offer many thanks in advance.

2. Originally Posted by dclary
Hello all. I am a newbie here and could really use some help with a math problem. I searched the boards and did not see anything similar so here goes...

The problems is:

Evaluate 2 – 20 ÷ (1/3 + 1/4) x 7

Now I understand the basic order of operations but these added fractions are throwing me off. I made an attempt at the problem by adding the fractions which came to 7/12 which I then turned into a decimal but I know that can't be right. If someone could explain this to me, I would really appreciate it and offer many thanks in advance.
Yes, your "order of operations" is correct. But why "turn it into a decimal"? Since the problem is expressed in terms of decimals, I would expect you to answer that way. 2- 20÷ (1/3 + 1/4) x 7 is, indeed, equal to 2- 20÷ (7/12) x 7 = 2- 20*(12/7)*7= 2- 20*12= 2- 240= -238.

3. Thank you for getting back to me so quickly. Let me make sure I have this correct, I keep the fraction without changing to a decimal and just solve the problem as I normally would...is that correct? If so, boy do I feel stupid! I have been tackling that problem for most of the day.

4. Yep, there's absolutely no need to convert these fractions into decimals!

The question is given in fraction form, so you can assume the teacher/examiner/book expects the answer in fraction form also (If the answer isn't a whole number of course :P)!

What answer did you get?

5. Boy, it is hard trying to do this math stuff after 20 year of not being in school....lol! When I first did the problem, I kept wanting to change the fractions to a decimal because I couldn't figure out how to work the fractions with the rule of PEMDAS. Just when I think I am getting some where, the Professor throws a zinger out and I get lost :-)

There were only 8 questions on this assignment and I have been 2 days trying to get them figured out...lol. There were two that was giving me a hassle, the one I posted here and one about equations. I might catch on one of these day.