Currently, I use write things like
\[
3 + 4 = \underline{\hspace{2cm}}
\]
in the exam paper I am preparing. The \underline
indicates where students should write their answer.
However, I want to change the underlines into empty boxes where students can fill in answers, such as a number. This allows me to control how large font they write.
$$ ... $$
in LaTeX, but\[ ... \]
instead or just$ ... $
if it's inline math. See this very extensive post about that.