I am looking at spreadsheets someone else built and seeing cells with
formulae like what's shown in subject.

I can see what it is supposed to do which is to sum the absolute value of
each cell referenced, which is something I want to duplicate elsewhere.

However, when I try to put that formula in the cell, it gives me #value! So
I'm just wondering how exactly was this done. I suppose the curly brackets
mean something but I don't know what.

Thanks.