This should be really easy, I am just terrible with excel.

I want to set up a personal finance database. It is a very easy worksheet
that just looks like this
A B C
1| Date | Change | Result |
2| Initial 0 500
3| 5/24/06 30 530
4| 5/25/06 -45 495

So on and so forth.
Now for C3 I wrote =SUM(C2,B3) and it gave me the right answer. However, how
do I make it so that every cell in the C column it always adds the number
above it to the number in the cell before it, without having to write the
individual equation in every cell?