A peculiar conditional sum

[THEGIOS]

Hi,

I've been trying for a few days to sort out a way to solve my peoblem but couldn't, so here I am :-)

Suppose you have range, let's say A1:A5, which can contain either a numeric value or an X, and then you have cell A6 whch is the sum of the above range.

My problem is that when all cells in range A1:A5 are X then A6 displays a zero, which I don't want: I want a blank instead.

The reason is that I need to distinguish between all zeroes in the range and all X, but in both cases in A6 I have zero.

I have tried in many different ways but nothing works, including the following

A6 = IF(ISNUMBER(A1:A5); SUM(A1:A5); "")



Thanks