here is the factorial module
the module is parented to a server script and the server script already has what you need to know
the script below is what is inside the server script
local FactorialModule = require(script.Parent)
local Fac = FactorialModule["!"]
print(Fac(5))
local Fac can be named anything it doesn’t have to be Fac() it could be also be math.fact() if you add a bit more stuff to it
I think I covered how to use it now have fun and please tell me if there are any bugs with this