Rnd()

The Rnd() function will calculate a random number between 0 and 1.  You can then multiple it by the top number of the random interval.  So if you wanted a number between 0 and 100 you would multiple it by 100 and also use the Int() function to only capture the integer portion.  In the second example I am looking for a number between 1 and 100, in order to do this I use 99 as the top number and add 1 so that if the random number comes out as 0 it will actually be 1 because I added 1 to it.

Script: 

'Random number between 0 and 100
Sub Main
    Dim random_number As Double
    random_number = Rnd() * 100
    MsgBox random_number
    MsgBox Int(random_number )
End Sub

'Random number between 1 and 100
Sub Main
    Dim random_number As Double
    random_number = Rnd() * 99
    MsgBox random_number
    MsgBox Int(1 + random_number )
End Sub

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