rounding in sig figs

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Sarah Blake-2I
Posts: 100
Joined: Fri Aug 30, 2019 12:16 am

rounding in sig figs

Postby Sarah Blake-2I » Thu Oct 03, 2019 12:49 am

When you have .4566 or .4565 and need to have 3 sig figs, do you round up? I am just looking for a little bit of help regarding rounding off the end of numbers when using sig figs.

Emily Chirila 2E
Posts: 60
Joined: Sat Jul 20, 2019 12:16 am

Re: rounding in sig figs

Postby Emily Chirila 2E » Thu Oct 03, 2019 12:55 am

If the last digit is 5 or greater you will round up. If the last digit is 4 or less, round down. In the case of .4566, if you needed 3 sig figs it would be .457 and for .4565 it would also be .457 because the last digit in both is 5 or greater.

TarynD_1I
Posts: 55
Joined: Sat Aug 24, 2019 12:17 am

Re: rounding in sig figs

Postby TarynD_1I » Thu Oct 03, 2019 9:33 am

Professor Lavelle also has a link on his website (https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf) that is really helpful for figuring out sig figs :)

Kaitlyn Jang 1F
Posts: 45
Joined: Sat Aug 17, 2019 12:16 am

Re: rounding in sig figs

Postby Kaitlyn Jang 1F » Thu Oct 03, 2019 10:25 am

You would round up to to .457. When the digit before the number of sig figs you are rounding to is greater than 5, you round up. If the digit is less than 5, you round down.

Isabella Dal Porto 1H
Posts: 49
Joined: Fri Aug 30, 2019 12:16 am

Re: rounding in sig figs

Postby Isabella Dal Porto 1H » Sun Oct 13, 2019 12:08 am

The link that Lavelle posted on his website for sig figs states the rule. If the last digit is 5 and no number follows it, then you have to round to the nearest even number. Thus, if you need three sig figs and you have 0.4565, you have to round to the closest even number which is 6. Thus, it becomes 0.456. I noticed one of the problems in the solution book followed this rule.

preyasikumar_2L
Posts: 60
Joined: Fri Aug 09, 2019 12:17 am

Re: rounding in sig figs

Postby preyasikumar_2L » Sun Oct 13, 2019 12:11 am

For rounding numbers that end in 5 in chemistry you want to try to round it to the nearest even number. 0.55 would round up to 0.6, 0.65 would round down to 0.6, etc. Usually when you have many numbers like this, rounding in this manner can somewhat "average" everything out. You would not round like that in any other math or science class though. So in this case, .4566 would round to .457, and .4565 would round to .456


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