math function add two fields and display results

[Daysurgery]

I would like to have the value of Field Y display the sum of Field R&T. I
have followed all the oblique instructions that Microsoft has come up with
and I get the error message that "The database engine does not recognize the
field in a valid expression." Cannot get out of design mode now

 

[Jerry Whittle]

Where are you doing this: form, report, query?

Please provide what you have tried so far.

 

[JEA via AccessMonster.com]

What to you mean be "Field Y"?

If you mean a table field you can't do it. Tables can't store calculated
data. You need to calculate it each time you want to use it in a query,
report or form.

If you mean a text box on a form or report make sure you reference the fields
correctly. If they are fields in a table use DLookup, if they are other text
boxes on the form or report use [textBoxName]. If they are on a different
form use [Forms]![FormName]![textBoxName].

If they are query fields in the calculated field use FieldName: [FieldR] +
[FieldT]