Significant Figures in Scientific Calculations

[Demiwing]

I don't really get the concept of significant figures. Anyone can help me out?
1200 X 23.4
What is that in significant figures?

 

[bomba923]

*Significant figures = "sigfigs"
Remember that products will have as many sigfigs as the least accurate multiplier.
Here, in your case, 1200 $\Rightarrow$ 2 sigfigs, and 23.4 $\Rightarrow$ 3 sigfigs.

*Therefore, the product will have two sigfigs, represented as $28000 = 2.8 \cdot 10^4$

->Just remember the sigfigs product rule here

 

[erok81]

I always hated those when I was first learning them. Here are the basic rules.

-All digits except zeros at the beginning of the number are significant.
i.e 9.12 (3) 0.912 (3) 0.00000912 (3)

-Terminal zeros @ right of decimal point are significant.
i.e 912.0 has four.


Multiplication and division;

Final answer has the same amount of significant figures as the number with the least sig fig in original problem.

i.e 34.987 x 54.2 = 1896.3

Addition and subtraction;

Final answer has the same number of sig fig as the number with the least number of decimal places.
i.e 12.9875 + 1.23 = 14.22


I think the best way to explain it is, you answer can only be as accurate as the least accurate answer. If that makes sense.


If you still don't get it, I have another way to explain but it's as long, if not longer than this. I don't really want to type that out yet. Haha.

Hope this helps.

 

[bomba923]

I always hated those when I was first learning them. Here are the basic rules.

Hmm, I always liked sigfigs, never hated learning them..

 

[GCT]

first term has two sig figs, the second has three, your final product should have two sig figs.

 

[erok81]

Hmm, I always liked sigfigs, never hated learning them..

Ok, not really hated. But they are easy to get confused on. So as I was learning them I can't say I liked them. :tongue2:

But after the first few minutes I liked them. Most of the class was still having problems with them by the end though.

 

[amcavoy]

The concept is very simple, but it is surprisingly easy to make a mistake when working with sigfigs.

 

[bomba923]

The concept is very simple, but it is surprisingly easy to make a mistake when working with sigfigs.

*Mostly I just double-check my work to ensure proper use of sigfigs
However, the stupid mistakes I do make :shy:, are just silly arithmetic errors (working under duress!), usually (+) sometimes (-). Though when working under pressure/duress...double-checking isn't always convenient