Form Caculation to Add even with blank Fields is incorrect Please help

[Karaline]

=(Nz[AddQuantity],0*Nz[txtRRate],0)+(Nz[Quantity],0*Nz[txtTRate],0)



Originally I had =([AddQuantity]*[txtRRate])+([Quantity]*[txtTRate]) and it worked until i entered a docket with a blank Add on field.

can someone please help recreate this for a form that is sending the calculated cost to the table.

I cant get the addition to work correctly and it was working the above way without Nz but sometimes the AddOn is not required and this caused the calculation not to work. I am trying to fix it but it just keeps saying I have an opera without an operator.

[ranman256]

=Nz([AddQuantity]) * nz([txtRRate]) + ( nz([Quantity]) * nz([txtTRate]) )

[Karaline]

Thanks in advance,
It looks as if i was over parenthesising yes I am australian, we don't use z's
and I added 0's where they weren't needed.
can i ask why no "0"? is there special circumstances where you add the ",0" onto calculation?

[Micron]

If the parameter is not provided, the default is either a zero or zero length string. In a case where more than one data type could be returned as a default, I would not omit specifying which I wanted as a safe guard. Not that it's wrong I guess, but why open that door if you don't have to?

You weren't over doing it. You had them in the wrong places. For most built in functions, what follows the function name must be enclosed. One exception would be Date().