How to deal with significant figures in decimals with zeros.

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Jenaye Brelland 2I
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How to deal with significant figures in decimals with zeros.

Postby Jenaye Brelland 2I » Thu Oct 08, 2020 7:05 pm

Hi! So I am a little confused on the whole trailing zeros and zeros in decimal point aspects. My question is: how do I deal with significant figures that are in-between numbers, but after the decimal point? For example, how many sig figs does 20.01 have?

Chem_Mod
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Re: How to deal with significant figures in decimals with zeros.

Postby Chem_Mod » Thu Oct 08, 2020 7:09 pm

Zeros, as in 20.01, do count as significant. In this example, 20.01 would have four sig figs.

Ethan Laureano 3H
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Re: How to deal with significant figures in decimals with zeros.

Postby Ethan Laureano 3H » Thu Oct 08, 2020 7:11 pm

20.01 has 4 sig figs. As for your base question, when there is a decimal point, all trailing zeros are counted in the sig fig count. However, when there is no decimal point, trailing zeros don't matter. Any zero in between numbers counts, regardless if there is a decimal. So 2001 will also be 4 sig figs.

Arti_Patel_3H
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Re: How to deal with significant figures in decimals with zeros.

Postby Arti_Patel_3H » Thu Oct 08, 2020 7:12 pm

I agree, 20.01 has 4 significant figures. If you wanted more clarification, Dr. Lavelle's website has this resource: https://lavelle.chem.ucla.edu/wp-conten ... OUT_SF.pdf

Nane Onanyan 1G
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Re: How to deal with significant figures in decimals with zeros.

Postby Nane Onanyan 1G » Thu Oct 08, 2020 7:15 pm

Anytime there is a zero between two significant numbers (non-zeros), it counts. So 20.01 will have four sig figs. Trailing zeros are ONLY significant if it is after the decimal point. So 20.010 for example would have 5 sig figs and 200 would only have 1.

Valerie Tran 2B
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Re: How to deal with significant figures in decimals with zeros.

Postby Valerie Tran 2B » Thu Oct 08, 2020 7:16 pm

If there are zeros "sandwiched" between two numbers, they are always included when counting sig figs. So for example, 2001, 2.001 and 20.01 all have 4 sig figs. Zeros in front of the decimal never count, so .002 or 0.000002 only have one sig fig. And if there are trailing zeros, they only count if there is a decimal, so 2000 is 1 sig fig but 2000. and 2.000 have 4 sig figs. This is probably more than you needed but hope it helps

TJ Lai 2H
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Re: How to deal with significant figures in decimals with zeros.

Postby TJ Lai 2H » Fri Oct 09, 2020 7:48 pm


Heidi Buri 2I
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Re: How to deal with significant figures in decimals with zeros.

Postby Heidi Buri 2I » Fri Oct 09, 2020 11:36 pm

According to the significant figures rules, all trailing zeros after a decimal point are considered significant. Additionally, all zeros that are located in-between other non-zero figures are considered significant. In the example you provided, I believe that there would be 4 significant figures. The zeros would be significant as they are located in-between the non-zero values of 2 and 1.

Alessia Renna 1D
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Re: How to deal with significant figures in decimals with zeros.

Postby Alessia Renna 1D » Sat Oct 10, 2020 10:57 am

Zeros that are in between integers are significant! In your example there would be 4 significant figures.

Jeffrey Fenn 1G
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Re: How to deal with significant figures in decimals with zeros.

Postby Jeffrey Fenn 1G » Sat Oct 10, 2020 11:25 am

There is a very good video on the website that goes over sig figs, I highly recommend it, it goes over all of this.

Sheryl Ocampo 1D
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Re: How to deal with significant figures in decimals with zeros.

Postby Sheryl Ocampo 1D » Sat Oct 10, 2020 11:49 am

20.01 has four sig figs. Whenever a 0 is between two significant digits, it's considered significant, regardless of whether it is before or after the decimal point. However, a trailing zero is only significant if it is after the decimal point.

Reese_Gover2K
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Re: How to deal with significant figures in decimals with zeros.

Postby Reese_Gover2K » Sat Oct 10, 2020 2:15 pm

There's a rhyme my high school chem teacher taught us to remember this. If there's a decimal preceding that end 0 has meaning and if there are nonzeros on each side, that 0 must reside. So in the case of 20.01 since there is a decimal preceding the zero that zero is a sig fig and since there are nonzeros surrounding the zeros those zeros are sig figs.

Sean Phen
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Re: How to deal with significant figures in decimals with zeros.

Postby Sean Phen » Sat Oct 10, 2020 2:23 pm

Zeros in-between numbers do count as significant figures. So, 20.01 has 4 significant figures. I always have struggles when determining if a zero is a significant figure. My tip is to look up the rules of significant figures and make a list with examples. With examples, I can compare it to other numbers as well because the concept is the same. To memorize these different rules, I usually make flashcards for each rule with an example.

Gicelle Rubin 1E
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Re: How to deal with significant figures in decimals with zeros.

Postby Gicelle Rubin 1E » Sat Oct 10, 2020 2:34 pm

Hi Jenaye! I literally was so confused as well when I was working on the Sapling homework not too long ago. But riding off of what others have said, the numbers are important if they're between 2 integers. However, I am still having some trouble understanding the decimal rule.

Sameer Chowdhury 3C
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Re: How to deal with significant figures in decimals with zeros.

Postby Sameer Chowdhury 3C » Sat Oct 10, 2020 3:13 pm

Here's a good link that explains what parts of a number are significant figures and which parts aren't. Also if you're ever really unsure as to the specific significant figures of certain number, this site provides you with a quick way to check if you got the number significant figures correct, after you've tried to figure it out yourself of course. https://www.calculatorsoup.com/calculators/math/significant-figures-counter.php

Kendall_Dewey_2D
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Re: How to deal with significant figures in decimals with zeros.

Postby Kendall_Dewey_2D » Sat Oct 10, 2020 4:21 pm

Here is another helpful link I have found for this topic! https://users.astro.ufl.edu/~rlpitts/Si ... igures.pdf

305405193
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Re: How to deal with significant figures in decimals with zeros.

Postby 305405193 » Sun Oct 11, 2020 10:34 pm

Here's also a YouTube that really helped me understand sig figs! It explains the rules with addition, subtraction, multiplication, and division. https://www.youtube.com/watch?v=BmeImtwhfj8

205323697
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Re: How to deal with significant figures in decimals with zeros.

Postby 205323697 » Sun Oct 11, 2020 11:15 pm

I have a little list that helps me with sig. figs.
1. All non-zero digits are significant
2. Zero's between non-zero numbers are significant
3. Leading zeros are not significant
4. Trailing zero's in a number showing a decimal point are significant

Minh Nguyen 3A
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Re: How to deal with significant figures in decimals with zeros.

Postby Minh Nguyen 3A » Sun Oct 11, 2020 11:19 pm

Zeros that are in between significant figures, like the example you gave in 20.01, count as sig figs. As such, 20.01 has 4 significant figures. For reference, leading zeros that come after a decimal point don't count as significant figures.

Jenaye Brelland 2I
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Re: How to deal with significant figures in decimals with zeros.

Postby Jenaye Brelland 2I » Sun Oct 18, 2020 10:08 am

Thank you for all the replies! What about how to determine what sig fig should your answer be in an addition or subtraction problem?

Andrew Yoon 3L
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Re: How to deal with significant figures in decimals with zeros.

Postby Andrew Yoon 3L » Sun Oct 18, 2020 9:49 pm

Once you have your answer, find the number with the least sig figs, and then apply the number of sig figs in that number to your answer.


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