Summation (Σ) help?

Already hit another snag...

What I need to do is use a summation as part of a calculation. For example, lets say I've got a list of numbers in column A and the equation in column B, where the equation for B1 uses the summation of the number in A1, B2 uses the summation of the number in A2, etc.

So if the equation in B1 was just =Σ(A1) and it was copied down, I'd get this:

A B
3 6
5 15
2 3
8 36

Is there any way to get excel to do this? I'm asking because my calculation requires the summation of several numbers (which are all variables) and trying to do it using pretty much every other method I can think of would take a lot of time to set up...

Try this

=SUMPRODUCT(ROW(INDIRECT("1:"&A1)))

Originally Posted by Bob Phillips

Try this

=SUMPRODUCT(ROW(INDIRECT("1:"&A1)))

That worked. Thanks. :3

Originally Posted by Moo the Dog

For summation, you can use:

=(A1*(A1+1))/2

- Moo

That also worked.

I'm rather surprised though that excel doesn't have a function for this, especially considering all the random things they DO have functions for...

Originally Posted by Moo the Dog

For summation, you can use:

=(A1*(A1+1))/2

- Moo

Brilliant!