Question about "Create Falling Snow - Explanation of Code" page

Hi,

I was trying to understand the code of this tutorial (create snow)
so i went to the explanation code page and there is some explanation that i have some problem with :

everytime something like :
x = a + Math.Random()*b;
is written i would have assumed (since Math.Random() return n with 0<=n<1) that x would be something like this :
a<=x<(a+b)
but the code explanation says that x take as values :
a<=x<b
and i cant get how this could be.

If anyone can answer my problem, thx in advance.


Paciv