PREP 2014 Question Authoring - Archived

round-off error and rounding

Re: round-off error and rounding

by Genevieve Toutain -
Number of replies: 0
This seemed to be the closest to the issue I am having, so I thought I would reply here to bump it to the top.  I am authoring a question that includes a random one decimal between -10 and 10, hence:

$a = random(-10,10,.1);

I just happened to have seed 1612, and when printing out $a in the problem, instead of printing -0.02 (as I suspect it wanted to), it is printing out -0.1999999999. 

Any ideas on what I should do here?  Is there a way to restrict how many decimal places WeBWork displays?  Is this a known issue?  I tried searching the forums to not much avail. 

I've gotten around this by replacing it with 

$a = random(-10,10)+random(0,1,.1);

which while technically not the same serves my purposes just fine.  I'm a little concerned there are other lurking decimal issues.