Decimals After Whole Numbers

Moderators: Chem_Mod, Chem_Admin

Kguox1B
Posts: 29
Joined: Mon Jun 17, 2019 7:22 am

Decimals After Whole Numbers

Postby Kguox1B » Sun Jun 30, 2019 11:11 pm

In class, we saw an example where the number "100." had 3 significant figures. Does the fact that there is a decimal point after change the sig fig in any way?

Chem_Mod
Posts: 18400
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 435 times

Re: Decimals After Whole Numbers

Postby Chem_Mod » Mon Jul 01, 2019 8:12 am

Yes. 100 only has 1 sig fig while 100. has 3 sig figs. The decimal part is an important factor if you are dealing with 0's.

Important too, .001 has 1 sig fig, while .100 has 3 sig figs for example. .00100 would have 3.

Jocelyn Thorp 1A
Posts: 103
Joined: Wed Sep 18, 2019 12:20 am

Re: Decimals After Whole Numbers

Postby Jocelyn Thorp 1A » Mon Sep 30, 2019 11:50 pm

Chem_Mod wrote:Yes. 100 only has 1 sig fig while 100. has 3 sig figs. The decimal part is an important factor if you are dealing with 0's.

Important too, .001 has 1 sig fig, while .100 has 3 sig figs for example. .00100 would have 3.


Thanks for the inclusion of the zeroes after the decimal but before any nonzero values. I always get confused when it's something like .000023;

I suppose the simplest way to remember (for me at least) would be if they would be significant if you were writing in scientific notation (ex: you wouldn't include the zeroes in .000023 as 2.3*10^-5 but you would for .3400 as 3.400*10^-1).

DMuth_1J
Posts: 63
Joined: Thu Jul 11, 2019 12:15 am

Re: Decimals After Whole Numbers

Postby DMuth_1J » Tue Oct 01, 2019 12:36 am

A good way to remember this that I always use is that, when writing normal numbers, you could also write 002, which is still two. But we intuitively ignore the zeros before the important digit. It applies similarly to decimals. For example, (.002) is still one significant figure.

Sara Richmond 2K
Posts: 110
Joined: Fri Aug 30, 2019 12:16 am

Re: Decimals After Whole Numbers

Postby Sara Richmond 2K » Tue Oct 01, 2019 7:40 am

Do any of you have a video recommendation to review significant figures? It has been a long time since I've looked at significant figures?

britthanul234
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

Re: Decimals After Whole Numbers

Postby britthanul234 » Tue Oct 01, 2019 8:38 am

Where the decimal point is placed is super important when it comes to significant figures. 100 would be 1 sig fig because you don't count the zeroes after the 1. However, 100. would be 3 sig figs because you must count all digits that come before the period as long as the digits coming before the decimal point are not all zeroes.

Sarah Zhari 1D
Posts: 103
Joined: Sat Sep 14, 2019 12:16 am

Re: Decimals After Whole Numbers

Postby Sarah Zhari 1D » Tue Oct 01, 2019 10:34 am

Here's quite a good video on sig figs: https://www.youtube.com/watch?v=hQpQ0hxVNTg (it starts from about 5:40)
The explanations are quite thorough.


Return to “Significant Figures”

Who is online

Users browsing this forum: No registered users and 1 guest