Problems in calculating amount due in a form

[SaraHans]

Hi I'm new to access and i have an assignment to complete.Can someone help me in calculating the amount due in the payment form.How do i do this?The amount due is adding the TreatmentCost of a Treatment and the(SellingPrice*Quantity) of Product from different tables.I am attaching my access program.

[JoeM]

I cannot download your database from my current location, but if you are dealing with two tables, try joining the tables in a query, and then using the query as the data source of your Form. You can either do the calculation in the query itself, and place that calculated field on your Form, or you can try doing the calculation right in the Form itself (I prefer to do them in the query, myself).

[Missinglinq]

Given that your app has 18 forms, it would probably help if you were to give us a clue as to which form you're referring to!

You should always remember, when posting, that you know what you're doing; we only know what you tell us!

Welcome to the forum!

Linq ;0)>

[SaraHans]

Given that your app has 18 forms, it would probably help if you were to give us a clue as to which form you're referring to!

You should always remember, when posting, that you know what you're doing; we only know what you tell us!

Welcome to the forum!

Linq ;0)>

Sorry
I was refering 2 the form payment
It has a field with amount due.
I have to combine the quantity which is in form salesline,sellingPrice which is in formProduct and the TreatmentCost which is in formTreatment to get the amountdue.
How do i do this ?