Calculated fields on a form

[Tony]

Hello
I have a series of related tables (and the relationships work fine on the
form) and I am trying to do a calculated field on a form :
I have added a textbox and built the formula
=[tblBrochures]![Quanity]-[tblOrders]![OrderAmt]
both the variables are "single"
But I get an error #Name? returned.
ideally i would like to have the Quantity assigned the value of
[tblBrochures]![Quanity]-[tblOrders]![OrderAmt].

Can someone please help?

 

[ghetto_banjo]

Are both of those fields, [Quantity] & [OrderAmt], bound to your form?

If so, you can just omit the table names altogether.

=[Quantity] - [OrderAmt]

 

[Jerry Whittle]

Assuming that both fields are already on the form or part of the form's
record source:

=[Quanity] - [OrderAmt]