One number to calculate them all...

I have an idea for a coding challenge but I'm new to programming so I'm sure how easy or difficult it might be, so you be the judge of that.

Do you know about these clock faces where instead of numbers it's just nines or threes calculating the numbers? (here's an example: https://www.cut-the-knot.org/arithmetic/funny/9Clock.shtml) there are also some riddles with this concept (https://www.wikiwand.com/en/Four_fours)

It'd be fun to see a programm that can show you how to calculate any number using only one number.
for example: I want to get 12 using only 3's. The programm would show me "3x3+3".