Do sig figs normally change the final answer significantly?

[kenhung123]

Surely it does take a few second per step to figure the sig figs per step (including identifying the least sig figs given in question)

[kenhung123]

Also, I read from Collin Li's post that in the exams they only check the question which they ask explicitly e.g. use 2 sig figs and they will decide to take off 1 mark or not

[Gloamglozer]

Surely it does take a few second per step to figure the sig figs per step (including identifying the least sig figs given in question)

Not really.  If you keep to around 4 sig figures in each step, then correct it to the right number of sig figs in the last step, then it shouldn't take that long.

[m@tty]

Yeah, it's only rounding. And identifying the required number of significant figures is quite easy too. When beginning a part of a question identify the least amount of significant figures appearing in the relevant data.
That won't take very long.

[the.watchman]

Yeah, it's only rounding. And identifying the required number of significant figures is quite easy too. When beginning a part of a question identify the least amount of significant figures appearing in the relevant data.
That won't take very long.

Yup, and it's good to work as accurate as possible throughout (while using exacts on the calc - store and recall) and writing values along the way to several sigfigs

[kenhung123]

Btw, so if the question gives 3 values e.g. 3, 4 and 5 sig figs, then do we even round the given values to 3 sig figs or leave it as it is on paper?

[superflya]

Btw, so if the question gives 3 values e.g. 3, 4 and 5 sig figs, then do we even round the given values to 3 sig figs or leave it as it is on paper?

in that case, ur final answer should be given to 3 sig figs.

[m@tty]

Yeah, the only thing that is altered according to significant figures is the final answer; nothing else changes.

[kenhung123]

But for example n=0.0345 c=0.12
n=CV=0.12x0.035 or 0.12x0.0345?

[the.watchman]

But for example n=0.0345 c=0.12
n=CV=0.12x0.035 or 0.12x0.0345?

Go for the second for the most accuracy BUT only round in the final answer

[m@tty]

This is wrong


This is the correct way.


Changing the measured values will void your answer.

[Cthulhu]

Yeah what I do is use all the full numbers and only round it off into significant figures for the result, but if that result is needed for the next question, I will use the full number of it, not the significant figure.
Significant figures are stupid!

Agreed, it's safest to work as accurately as possible throughout until the very end

http://www.stewartcalculus.com/data/CALCULUS%206E%20Early%20Transcendentals/upfiles/6et_liesmycomp_stu.pdf

[the.watchman]

This is wrong


This is the correct way.


Changing the measured values will void your answer.

Exactly

Yeah what I do is use all the full numbers and only round it off into significant figures for the result, but if that result is needed for the next question, I will use the full number of it, not the significant figure.
Significant figures are stupid!

Agreed, it's safest to work as accurately as possible throughout until the very end

http://www.stewartcalculus.com/data/CALCULUS%206E%20Early%20Transcendentals/upfiles/6et_liesmycomp_stu.pdf

That's quite interesting

[kenhung123]

Btw, how do you know how many sig figs to use? Is it just the least accurate you use in the specific calculation or least accurate provided in question?

E.g. they give C=0.15M, V=0.112L, P=1kPa

n=CV
 =0.15x0.112 (in calculations 2 sig figs is least accurate but in question the least accurate is 1 sig fig)

[akira88]

Btw, how do you know how many sig figs to use? Is it just the least accurate you use in the specific calculation or least accurate provided in question?

E.g. they give C=0.15M, V=0.112L, P=1kPa

n=CV
 =0.15x0.112 (in calculations 2 sig figs is least accurate but in question the least accurate is 1 sig fig)

You use one sig fig as the pressure is only one sig fig of "1kPa"