sum() empty cells not = 0

[lezawang]

Hi
I have seen some invoices template (File-->New--> Office Templates), in these templates they have function like this

=sum(A1*B1)

and both cell A1 and B1 are empty but the sum() does not return 0!!
I check the cell, no other function except sum(), I thought they used iferror() or if() zero etc but no nothing there. How can this be done?

Thanks

 

[RoryA]

Which template and what does appear in the cell?

 

[Jonmo1]

There's a few ways to hide 0's.
Custom formatting - Try clearing Formats

or

File - Options - Advanced
There's a checkbox called "Show a zero in cells with zero value"
UNchecking that box will hide zeros.