\documentclass[hidesidemenu]{webquiz}
\title{An answer with comparison=integer}
\begin{document}
  \begin{question}     % a quiz question
     How long is a piece of string?
     \answer[integer]{18} mm (Correct answer $18$)
     \whenRight Yes, $18$mm pieces of string are $18$mm long!
     \whenWrong Incorrect! Is your ruler working?
  \end{question}
\end{document}