How to make a properablity eqautions

Hello MathWorks,

I want to make a program that calculates properablity or chances of selected numbers. However I also want to make a program that show the selected numbers. For explain you know how fliping a coin is 50/50 but when you flip its either head or tails. I would like to make a program where I can have a setting or range of numbers between for ex 1 to 10 and the program run 3 numbers between that range and tell me its probability. I know its simple i just dont know how to do it. Thank you