Hi, can anyone tell me how to change the value of an empty cell to a zero
please?

I am using =SUM(A1-B1 A2-B2 A3-B3 and so on)

It performs the sum ok and everything, but when one of the cells is blank,
it just returns a #VALUE massage, because its being asked to sum blanks etc.
How can I get around this please, and have a zero appear in the answer cells
(C1 C2 C3 etc)??

Thanks in advance,

Ted.