You are reading documentation for Twine 1. This is maintained for archival purposes only.
When given two positive numbers, this produces a positive whole number randomly selected between the two, inclusive. This function can (and should only) be used to generate random numbers within a wide range - such as 1 to 100.
Prior to version 1.4.2, you had to use the cumbersome
Math.random(value)*value idiom to do this, which wasn't that memorable or succinct.
You have a <<print random(1,99)>> percent chance of complete and utter defeat!