How do I stars ranking?

Hello guys. My doubt is about how can I put a system of stars at my memory game. There are phases on the game and I wanna that the players gain stars (three max) acoording to their matched cards.

I'm sorry please explain a bit more.

Do you mean you want help on how to store a score?

Or do you want help with making the matching cards in the game?

So what is your question about - calculating the stars, displaying them?

Record the number of correct answers. (correct/total)*100 gives you the percentage of correct answers. Then you can decide how many stars to give, say 3 stars for 100%, 2 stars for ≥50% or 1 star if <50%