7 minutes ago, Dramolion said:

Writing out 4 solutions on a card is a lot more space-consuming then adding "x1" "x2" and "x3" to these instructions to make the rewards differ.

It's an educational/teaching game.  It's important that they chose from four possible solutions.  The type of solution they chose is paramount to how well they are doing in the game.  So it's not just a matter of adjusting random scoring points.  It's not a game of luck, it's a game of awareness and understanding of what solutions are most appropriate for a given type of problem.

By the way, I just thought of a clever idea on how to hide the problem type from the players and reveal it at that same time in a way that they won't recognize but will still be able to use the information for proper scoring.

So this can potentially be made into a board game with card instructions after all.