Are you trying to do a dice rolling script or something?
And, do you know about $rand? If you're $reading random numbers from a text file and if those numbers include numbers that do not skip (e.g. 10,11,12,13,14 instead of 10,14,17,23,24), then you can just use $rand.
//echo -a $rand(10,19)
//echo -a $calc($rand(1,100) - $rand(1,19))
