Give a number between $lower and $higher.
# We do not want a vector
if ($submission=~/\,/) { return 'EXTRA_ANSWER'; }
# No units needed
if ($submission=~/^\d+\s+\w+$/) { return 'UNIT_NOTNEEDED'; }
# Need a numerical answer here
if ($submission!~/^[\d\.]+$/) { return 'WANTED_NUMERIC'; }
# is it correct?
if (($submission>=$lower) && ($submission<=$higher)) { return 'EXACT_ANS'; }
return 'INCORRECT';
What do you get if you add $add to your number?