I don't know how can I explain... I'll try:

I have a list like this:
A
11,11
33,22
11,55
66,55

And I have to subtract 22 from this list and I want a result like this:

C
0
22,33
11,55
66,55

After, I have to subtract 30 from this new list and I want a result like
this:
D
0
0
3,88
66,55

....

My list has more a lot of lines. And maybe I'll have to subtract more
values...

1- How can I calculate the column "D"?
2- Can I have a one column with this results? Without the column "C"?

Sorry for my poor english

--

Rodrigo Ferreira