Inserting arithmatic formula in a field of a table

[MAIL@DC]

Attached here two screenshots.



Table can not be saved.

[Welshgasman]

Not going to download an unzip for such a question.
On this occasion a picture(s) is worth a thousand words.

Just post the pic(s).

[Bob Fitz]

Attached here two screenshots.

Table can not be saved.

You need to change the field type to Calculated (not Currency) but I wouldn't put calculations in a table. IMHO it is better to have calculations in a query.