SUMPRODUCT of positives and negatives values

[STFG]

Hi everyone,

I'm using a formula that works perfectly but there is just one small issue.
I need to do the sumproduct of positives and negatives values.


SUMPRODUCT(--(1+MOD((COLUMN(M21:CD21)-COLUMN(M21));9)=1)*(M21:CD21<0)*N(+M21:CD21))

This one is only for negatives values. So if ever I have - 6, - 4 and 2 the result is - 10 and I need to make excel doing the substraction so the final result will be 8 in this case.

Don't seem very difficult but I still can't find the answer in internet.

Thanks

 

[STFG]

Expected final result

- 8 not + 8