Re: Rounding?

*To*: mathgroup at smc.vnet.net*Subject*: [mg60885] Re: [mg60881] Rounding?*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Sun, 2 Oct 2005 01:54:37 -0400 (EDT)*References*: <200510010655.CAA13187@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On 1 Oct 2005, at 15:55, Tom De Vries wrote: > Hello everyone, > > Sorry if this is an obvious question. I'm wondering why the two > results > below are different? > > I'm creating programs to generate test questions, and I need to > know that my > computer generated answers will match the student answers, to say, > three > decimal places. So the answer is -0.0625 "exactly", the first > result makes > sense to me, the second doesn't. > > If there is a reason for this, is there are way to insure I can > make the > first result look like the second result all the time?? > > > SetAccuracy[-0.0625,4] > > -0.063 > > ToString[SetAccuracy[-0.0625,4]] > > -0.062 > > > Thanks for your input! > > > Tom De Vries > > This is because ToString by default uses the OutputForm of your expression: OutputForm[SetAccuracy[-0.0625,4]] -0.062 Compare this with: ToString[SetAccuracy[-0.0625,4],TraditionalForm] -0.063 and ToString[SetAccuracy[-0.0625,4],InputForm] -0.0625`2.7958800173440745 Andrzej Kozlowski

**References**:**Rounding?***From:*Tom De Vries <tom_toad@telus.net>