OK - well, from the helpfile:-
Rnd Function
Returns a Single containing a random number.
Syntax
Rnd[(number)]
The optional number argument is a Single or any valid numeric
expression.
Return Values
If number is Rnd generates
Less than zero The same number every time, using number as the seed.
Greater than zero The next random number in the sequence.
Equal to zero The most recently generated number.
Not supplied The next random number in the sequence.
Remarks
The Rnd function returns a value less than 1 but greater than or equal
to zero.
The value of number determines how Rnd generates a random number:
For any given initial seed, the same number sequence is generated
because each successive call to the Rnd function uses the previous
number as a seed for the next number in the sequence.
Before calling Rnd, use the Randomize statement without an argument to
initialize the random-number generator with a seed based on the system
timer.
To produce random integers in a given range, use this formula:
Int((upperbound - lowerbound + 1) * Rnd + lowerbound)
Here, upperbound is the highest number in the range, and lowerbound is
the lowest number in the range.
Note To repeat sequences of random numbers, call Rnd with a negative
argument immediately before using Randomize with a numeric argument.
Using Randomize with the same value for number does not repeat the
previous sequence.
