Need help in Excel?

Question

Look what's the problem.
I have 3 columns ....every column have 3 rows...and in every row is an number...negative or positive....I want another 2 rows at the end of every column...in the first row to be the sum of the numbers <0 and in the second the sum of number >0
I have made an screenshot or what I want and I don't know how to do this in Excel
You can see here an exemple:
http://img130.imageshack.us/img130/3253/exempleif1.gif
The red numbers are given numbers.
The blue numer is the sum of the negative numbers in that column and the green number is the sum of positive numbers in that column.
Please tell me the function for A4 and A5...or how to solve this problem
Thanks a lot!

Answer 1

Quite easy:
=SUMIF(A1:A3,"<0",A1:A3)
=SUMIF(A1:A3,">0",A1:A3)

Answer 2

The formulas below work in any spreadsheet (I don't have Excel). Select A4:A13 and fill across to B & C.
.. |........... A........... |
. 1|....................... 1 |
. 2|...................... -3 |
. 3|...................... 4 |
. 4| =SUM(A7:A9).... |
. 5| =SUM(A11:A13). |
. 6|.......................... |
. 7|=IF(A1>=0,A1,0). |
. 8| =IF(A2>=0,A2,0) |
. 9| =IF(A2>=0,A2,0) |
10|.......................... |
11| =IF(A1<0,A1,0).. |
12| =IF(A1<0,A1,0).. |
13| =IF(A1<0,A1,0).. |