Excel Column Formula

[grandmaster]

I have done this before..but I cannot remember how:
input a formula for an entire column (that calcs values individually
for each row), that takes different values for each calculation from a
different column.

ex: I have column a and b with numbers, and column c that I want the
summation of these values (individual rows).

Please help me out!

 

[Max]

Perhaps you mean, in say, C1: =SUM(A1:B1)
and then C1 is copied* down
*with the fill handle at the bottom right corner of C1 dragged down

 

[David McRitchie]

Based on the example of what you want.

A2: 3
B2: 5
C2: 8
D2: =SUM(A2:C2)

you can use the fill handle to copy the formula in D2 downward
http://www.mvps.org/dmcritchie/excel/fillhand.htm

If you want to put a sum for D2155 in D156
D156: =SUM(D2155)
but it would be better to write that as
D156: =SUM(D2:OFFSET(D156,-1,0)
see http://www.mvps.org/dmcritchie/excel/offset.htm
so that you can insert a row immediately before the total.
and you can use the fill handle by dragging to the left to
total columns A, B, and C as well.

This is very basic usage in Excel
You might want to look at some Excel tutorials such as those
for university students see
http://www.mvps.org/dmcritchie/excel/excel.htm#tutorials