2 significant figure problems

[Bubofthedead]

1. The problem statement, all variables and given/known data

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?


2. Relevant equations



3. The attempt at a solution

Attempt on #1: 955.33 g (wrong ans)
Attempt on #2: 2 sigfigs (wrong ans)
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution

[LowlyPion]

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?

[Bubofthedead]

Yeah, the km/s was a typo, i was looking at #2's units when I was typing.

[Redbelly98]

3. 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?

[Banaticus]

3.5 g
I only see two numbers right there. Does that help?

[tiny-tim]

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.