Reply to OP's email received:

Welcome, but kindly keep all discussions online in the newsgroup thread, not
via private email to me. Upload the link to your new sample and post your
responses there.

Particularly 60,000,000.00 and its opposite showed up as "not cancelling"

Assuming the formulas are all correctly installed, and all source numbers in
col A are real numbers, one possibility is that the 2 numbers are not
exactly equal. One may be fractionally off the other (the real underlying
value), despite how they appear in the cells.

Try a simple test.
If the 2 numbers are in cells A5 and A10 (say),
in an empty cell, put: =ABS(A5)=ABS(A10)
If the numbers are really equal,
the return should be TRUE

To cater for the above possibility, we can use ROUND() in the array formula
in col C to round off all source values to say, 2 dp in the comparison

So in C1, array-entered, copied down:
=IF(B1="","",IF(ISNUMBER(MATCH(-ROUND(A1,2)&"_"&ROUND(B1,2),ROUND($A$1:$A$100,2)&" _"&ROUND($B$1:$B$100,2),0)),"",ROW()))

Adapt the ranges to suit.
--
Max
Singapore
http://savefile.com/projects/236895
xdemechanik
---
--- pogster wrote:

Hey Max,

Thanks so much for attempting a solution to my
Madenning Dilemma.
Your solution is a great one, although it does not
completely work to
my dataset.
I attempted your formulas on my dataset on my own (i
did not look at
your application on my test sample), and the
formulas failed to flag a
bunch of cancelling pairs.

Particularly 60,000,000.00 and its opposite showed
up as "not
cancelling", when they in fact should cancel out. I
will upload or
email to you a copy of MY test results sometime
tonight.

Thanks again for your great attempt! But this one
seems uncrackable so
far.

-Pogster