calculation between main form and subform

[jaomata]

I have a form that has a subform. In my main form, I have an AMOUNT field. In the subform, I have TOTALAMOUNT field. I would like to create a text box in my main field that would calculate the difference between the TOTALAMOUNT and the AMOUNT fields. Please help me. I think this is very easy for you all.

 

[pcs]

create a text field with its control source set to:

[yourSubFormName]![TOTALAMOUNT]-[AMOUNT]

hth,
al