Inserting arithmatic formula in a field of a table

[MAIL@DC]

I am new to access 2007. Want to insert arithmatic formulae in the fields. The formula is written in the 'description' in design view.


Gone through several help articles.
No 'calculated field' option can be noticed.
Kindly help.

[Welshgasman]

Calculated fields do not exist in 2007.
You would calculate that in VBA.

The GST rate would be held in a table somewhere with dates applicable for that rate.
Quite likely not to have Total Amount as that can be calculated?

Also do not have spaces in field names. More work for you. Either name them with CamelCase TotalAmount or use _, Total_Amount.

No need to start another thread as well.