I'm trying to get back into physics, and was brushing up on some very basic concepts. I came across this problem on a website tutorial.(adsbygoogle = window.adsbygoogle || []).push({});

"Solve -9.300 + 2.4 * 3.21"

It's a problem to practice rounding with significant figures. The instructions say to round to significant figures only when you reach a final answer.

So here's what I did.

2.4 * 3.21 = 7.704 (I left the three decimal places as the instructions say to only round at the end.)

-9.300 + 7.704 = -1.596

So I came up with an answer of -1.596, since there are 3 significant figures after the decimal place in both numbers for the addition portion of the problem.

But the website says the answer is -1.6

I don't understand why they rounded to two sig figs. Is this an error on the website, or am I not understanding something?

This is the website for anyone who wants to check it out. The problem is about midway down the page.

http://library.thinkquest.org/10796/ch1/ch1.htm

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# Homework Help: Need someone to double check a simple problem with sig figs

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