in C3:

=IF(A3="","",IF(A1*A2=A3,"Good","TryAgain"))

Will this do?

"Teacher in Revetal" wrote:

Can anyone help me? I need a function that provides the following:
If a1*a2=a3, then show Good, else show Try again. This function is written
in c3, and I can make it work. But if a3 is a blanc, i want to show c3 as a
blank without ruining the function in c3. Is this possible? My students are
making a math-game.