Click form frmMainBig.
This shows a single customer (tblCustomers) who is buying 3 products (tblQuoteDetails - see the green bits).
Specifically, note the "line value" in green.
Now look at the orange field at the bottom of the subform.
I want the orange to show the sum of the "line values".
i.e. the Orange should show the sum of the green "line value"
I have tried various options but am unsure of my approach.
All help appreciated! I hope this is clear.