Hi,
> On Dec 4, 2015, at 2:41 PM, Jacob Bond <bon...@purdue.edu> wrote:
>>
>> Are you actually looking for the fraction to be reduced? Because we can
>> check that very generally.
>>
>
> Yes, that is the main idea.
Okay, then I would use Maxima to figure out if the reduced fraction is equal to
the fraction input by the student, see below.
- Gerd.
<problem>
<script type="loncapa/perl">
$a=&random(20,100,4);
$b=$a+&random(40,140,4);
$numerical=$a/$b;
$reduced=&cas('maxima',"$a/$b")
</script>
<startouttext />
Input $a/$b as a reduced fraction.
<endouttext />
<customresponse answerdisplay="$reduced">
<answer type="loncapa/perl"># Split nominator and denominator
($nominator,$denominator)=split(/\//,$submission);
# Do we have a nominator? If not, be nice and don't charge a try
unless ($nominator) { return 'BAD_FORMULA'; }
# Is it valid? If not, don't charge a try
$nominator=&cas("maxima",$nominator);
if ($nominator=~/^Error/i) { return 'BAD_FORMULA'; }
# If students just input a number, there would be no denominator
unless ($denominator) {
# Check for exact numerical equivalency:
if ($nominator==$numerical) { return 'EXACT_ANS'; }
} else {
# There is a denominator
# Again, be nice and don't charge a try for syntax errors
$denominator=&cas("maxima",$denominator);
if ($denominator=~/^Error/i) { return 'BAD_FORMULA'; }
# Okay, let's compare the fractions as strings
if ("$nominator/$denominator" eq $reduced) { return 'EXACT_ANS'; }
}
# Nope, sorry.
return 'INCORRECT';</answer>
<textline readonly="no" spellcheck="none" />
</customresponse>
</problem>
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