Significant figures [ENDORSED]

[Alondra Cervantes 1F]

Can someone please further explain how many significant figures to use when writing an answer. I am still a bit confused.

[Chem_Mod]

plz refer to the following doc to check what you need to know about sigfig
https://lavelle.chem.ucla.edu/wp-content/supporting-files/Chem14A/EVERYTHING_YOU_WANTED_TO_KNOW_ABOUT_SF.pdf

[Alondra Loera 1A]

Significant figures are the number of digits in an answer relative to the numbers in the problem.

11.2 has 3 significant figures
11.20 has 4 significant figures
0.011 has 2 significant figures

with decimals, the significant figures are counted after the first integer so for 0.011, 1 and anything after counts as a sig. fig.

This Khan Academy video is very helpful as well https://www.khanacademy.org/math/pre-algebra/decimals-pre-alg/sig-figs-pre-alg/v/significant-figures

[Sara Juarez 1B]

The number of significant figures will depend on the problem. If I am not mistaken, I believe you look to your original problem and look for the number that has the smallest significant figure and go off of that. Significant figures don't take into account leading 0's. So 0.1 and 0.000001 are both 1 sig fig. However trailing 0's are significant. 0.0102 is 3 sign figures because the first non zero number starts with 1 and than it is followed by two additional numbers.

[EmmaSkeie 1F]

Hi,

For quiz 1: If we are given a problem that has 3 different values, each of different number of significant figures (say the least number of SF is 2), do we round off the other numbers to 2 SF for every step, or do we keep the values given and then round off the answer to SF at the very end?

Thank you!

[Chem_Mod]

The rules for rounding are also described in the link of the endorsed post.

[Rob_Carter_1L]

Just confirming, I know that 0.0100 would have 3 sigfigs due to trailing zeros, but would 1.00 have 3 as well? Is it the same after decimal points?

[Kathy Vu 3L]

Just confirming, I know that 0.0100 would have 3 sigfigs due to trailing zeros, but would 1.00 have 3 as well? Is it the same after decimal points?

Yes, 1.00 would have 3 significant figures as well since the 2 zeros are trailing zeros behind a decimal point

[Kathy Vu 3L]

Is there usually a range of answers we can put on quizzes and exams, or is there only 1 answer that is allowed?

For example what if my answer is 2.5, but others got 2.6 due to a different amount of decimals used during calculations

[Chem_Mod]

I provide all students with the same constants, equations, and periodic table.
Therefore all students should have the same answer if sig-fig and round-off are done correctly.