You can try
Random r = new Random();
int rInt = r.Next(0, 100); //for ints
int range = 100;
double rDouble = r.NextDouble()* range; //for doubles
Have a look at
Random Class, Random.Next Method (Int32, Int32) and Random.NextDouble Method
Try below code.
Random rnd = new Random();
int month = rnd.Next(1, 13); // creates a number between 1 and 12
int dice = rnd.Next(1, 7); // creates a number between 1 and 6
int card = rnd.Next(52); // creates a number between 0 and 51