Pete,

Thanks so much for your attempt at this problem.

It is very important that all of the positives cancel with all of the
negative and leave the unique values untouched. A -10 should only
cancel with a single +10, etc...

I have tried a variation of the suggestion you offered, and though it
works in a case where this does not come into play, my needs require a
very accurate canceling of unique opposing values.

I wish there was a way i could just post the raw list of values i am
working with so it would be easier to understand.

Thanks again for your help Pete.