How Do You Solve Problems With Significant Figures?

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The discussion revolves around solving problems involving significant figures in measurements. For the first question, the correct sum of 896 g, 55.2 g, 0.63 g, and 3.5 g should adhere to significant figure rules, which dictate that the result should match the smallest number of decimal places from the inputs. The initial answer of 955.33 g is incorrect due to this rule. In the second question regarding the measurement 60,000,000 km/s, it is clarified that trailing zeros can be significant depending on context. Understanding these rules is crucial for accurate calculations in scientific contexts.
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Homework Statement



Question 1.
Find the sum of the measurements 896 g, 55.2 g, 0.63 g, and 3.5 g.

Question 2.
How many significant figures are in the measurement 60,000,000 km/s?

Homework Equations


The Attempt at a Solution



Attempt on #1: 955.33 g (wrong ans)
Attempt on #2: 2 sigfigs (wrong ans)

Homework Statement


Homework Equations


The Attempt at a Solution

 
Last edited:
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Bubofthedead said:
Attempt on #1: 955.33 km/s (wrong ans)
Attempt on #2: 2 sigfigs (wrong ans)

The first question is asking for grams not km/s
In the second question is a trailing 0 considered significant?
 
Yeah, the km/s was a typo, i was looking at #2's units when I was typing.
 
Bubofthedead said:

The Attempt at a Solution



Attempt on #1: 955.33 g (wrong ans)

You did the math correctly. What do the significant figure rules say for addition/subtraction?
 
Bubofthedead said:
3.5 g
I only see two numbers right there. Does that help?
 
Hi Bubofthedead! :smile:

You'd better read http://en.wikipedia.org/wiki/Significant_figures

In particular:
For addition and subtraction, the result should have as many decimal places as the measured number with the smallest number of decimal places.
 

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