La calculatrice cassée

you know the challenges of broken calculator?   The goal is to get the required number using a rather special calculator: - some keys are not available, - other keys are broken, you can only use them once, twice, three times ... or not!   To achieve the highest score, answer as quickly as possible by finding the optimal solution (the one that requires the least calculations).   With 5 difficulty levels, this game will delight young and old, children, teenagers, adults or winners of the Fields Medal!