evaluate empty cells as zero in formula?

Hi there,

I would like to add up the values of several cells
(with certain weights attached to each cell),
some of which are zero,
but trying to do so get no value as a result.

I've thus decided to treat all empty cells as zeros,
but don't know how to tell Excel to do that.

Alternatively, I tried to reproduce the whole table with "IF..." formulae
such that all empty cells would be replaced with zeros
and all others with their previous values,
but couldn't manage to do that:
However I constructed the IF... thing,
the empty cells remained empty,
so I couldn't apply my addition to them.

Any suggestions?

Many thanks,
Chris

When you say "empty" cells, are you sure they are completely empty and don't contain blanks, e.g. " "?

When you try to work with the empty cells, do you get a #NA in the cell?