Gui Random Math Pop up?

Ok, so I'm trying to make an event join pop up. So it uses random math but I don't know how to use random math so, please help me.

What exactly is random math? Do you mean math.random? math.random or Random are used to generate random numbers.

math.random takes 2 arguments, min number and max number from which it will then generate the random number. If none are given it will generate random number from 0 to 1.

math.random(1, 10) -- random numbeer from 1 to 10
math.random(1, 1.5) -- always 1, math.random can't generate number with digits, use Random instead
math.random() -- random from 0 to 1 (ex. 0.88859345) (Interesting that here it can generate number with digits)

Otherwise i really have no idea what do you mean by Gui Random Math Pop up.