## When should one start rounding in a problem?

Jose Robles 1D
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

### When should one start rounding in a problem?

For instance, when finding mass ratios I would divide an assumed amount of Hydrogen by its atomic weight; should I divide by 1 or its actual weight of 1.007 (I've seen both actions performed in a discussion)? These questions tend to deal a lot with assumptions so insight would help me a ton.

eduardomorales5
Posts: 77
Joined: Fri Aug 30, 2019 12:15 am

### Re: When should one start rounding in a problem?

It is best to round by the end of the problem and keep the precision of numbers during the problem to reach a more accurate answer. If you round too early, you might get a slightly lower or higher answer than what is correct. I would keep it at 1.007 for the sake of accuracy.

Jose Robles 1D
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

### Re: When should one start rounding in a problem?

Makes sense, I wouldn't want to determine my empirical formula from a simple rounding off the top of my head. Thanks for the fast reply.

Ashley Kao 1H
Posts: 50
Joined: Thu Jul 25, 2019 12:16 am

### Re: When should one start rounding in a problem?

Yes, I agree! When finding the molar ratio, I would utilize the most precise atomic mass of all of the different elements. This will ensure that your answer is as close to accurate as possible. Once you complete this, then rounding or considering significant figures is necessary.

Salma Fawzi 4G
Posts: 50
Joined: Wed Sep 18, 2019 12:20 am

### Re: When should one start rounding in a problem?

it's better to round your final answer so your calculation can be correct. If you round each step of your problem, then your sig figs might be incorrect towards the end.

sbottomley3a
Posts: 50
Joined: Wed Sep 18, 2019 12:19 am

### Re: When should one start rounding in a problem?

It's a good rule of thumb to always round at the end of solving. That way, your numbers are as precise as possible and you don't lose anything important in the actual calculation portion.

Elizabeth Harty 1A
Posts: 125
Joined: Sat Jul 20, 2019 12:16 am

### Re: When should one start rounding in a problem?

If you are waiting to round your answer until the end of the problem, how do you know how may decimal places/sig figs to use?

Sanjana Borle 2K
Posts: 111
Joined: Fri Aug 09, 2019 12:15 am

### Re: When should one start rounding in a problem?

You should probably keep from rounding until the very end, then round; I believe that is the most accurate.

Posts: 102
Joined: Wed Sep 18, 2019 12:21 am

### Re: When should one start rounding in a problem?

you should be as accurate as possible when doing you calculations and then round at the very end to accommodate for sig figs.

Nathan Rothschild_2D
Posts: 131
Joined: Fri Aug 02, 2019 12:15 am

### Re: When should one start rounding in a problem?

in response to how to know how many sig figs to use in the end, you should use the question in order to determine the number of sig figs in the end. So if the question gives 3.48 grams then your final answer should be 3 sig figs because that's how many sig figs the question had

MBouwman_4A
Posts: 40
Joined: Wed Sep 18, 2019 12:21 am

### Re: When should one start rounding in a problem?

It’s best to round at the very end of the problem once you have an answer so that you are more precise. Rounding during steps in the problem can result in errors.

Celena Kim 2I
Posts: 106
Joined: Sat Sep 14, 2019 12:17 am

### Re: When should one start rounding in a problem?

Agree with the above! Rule of thumb is to round your answer only at the end to get the most precise and accurate answer. Otherwise, errors might be carried throughout the steps and affect your final answer.