Originally Posted by
June7
The Requery method is to requery things like form RecordSource and combo or list box RowSource. A textbox has neither.
Textbox expressions will recalculate automatically whenever one of the term's values changes. Calculated data does not automatically save to a field in table and really should not be saved to table. Calculate the value whenever needed.
Arithmetic with null produces a null result. If any of the terms is null the result will be null. Deal with possible null.
Nz([A1],0)+Nz([A2],0)+Nz([A3],0)+Nz([A4],0)