You insert 3 numbers. More Than, Less Than, and Multiple Of. When you want it to just be a random number set the multiple to 1. Please don't make it so the number could be or will be over 100 times your multiple. Also make sure that the number fits in between the More Than and Less Than so you can get a number instead of an error.
I actually created this by myself so I could get a random number of the multiple of 18 for a Bar Mitzvah in May.