Police Officer needs help

[CHPolice]

I have a brain cramp.

Very simple calculation in a form.

Simple table and form. 3 fields. Field1, Field2 and
Total. In my form in the Control Source of the Total
field I have a simple calculation, =[Field1]-[Field2].
Here is the brain cramp. In the form the Total field
calculates but doesn't save the calculation to the table.
My mistake is either, the calculation shouldn't be in the
Control Source or I have written the calculation wrong.

(Just info, the table and form is being used to track
miles. The officer enters his start and ending miles and I
want the total field to be automatically populated).

ET (e-mail address removed)

 

[Allen Browne]

See:
Calculated fields
at:
http://allenbrowne.com/casu-14.html

The article explains when and how to store a calculated result.