Summing values in a range

[z thompson <cublai lastamericanempire com>]

Hi, 

I just started using gnumeric and have a question about a function to
sum values in a range given min/max values. Essentially, I have two
rows of three columns which would look similar to the following:

A       B       C
0       3       0
1       5       2


What I would like to do is:

(sum of row x + 1) - (sum of row x) = y

and then get the sum of the integers from 0 to y. So, essentially it would
be:

(1 + 5 + 2) - ( 0 + 3 + 0) = 5     sum of 0 to 5 = 0 + 1 + 2 + 3 + 4 + 5
= 15


Getting the difference between the rows is trivial. However, is there
a predefined function for summing the range 0 to y? If not, how could I
go about doing this?

Thanks for the help,
Zach Thompson