Check out Rounding to a Given Number of Significant Figures Rather Than Decimal Places for some definitive answers to your question. Also you may want to use the 'Search' facility before posting a question next time (I got that node simply by entering 'significant figures' into the search box) as they're likely to have been asked before (and failing a simple search, there's always Super Search).
HTH

_________
broquaint

In reply to Re: reducing numbers by broquaint
in thread reducing numbers by Anonymous Monk

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