Are you talking about a Word form?  If so, you would do better to ask in a
Word group.  This group is for Access, a relational database program.

Sean...
If you're refering to VBA, you access any field from any form within the same
document. Just make sure you're referencing the object correctly.

iNum = CInt(tNum.Text)
iPercent = CInt(tPercent.Text)
iPercent = iPercent * .01
iAnswer = iNum * iPercent

frm1.txtAnswer.Text = iAnswer
frm1.txtAnswer.Enabled = False

...my stab at it

First off when you create your form the table that contains your data must be
used in order to select the correct data fields.

1. Create your form with the two fields containing your data, "field1" and
"field2". Select the fields and place them on the form "form1".

2. Then place a blank "text box" from the controls list onto the form. On
the  properties field "controlsource"  of the "text box", select "Expression
Builder"  and then select "form1" if that is the name of your form. When you
select "form1" you will see the fields attached to form1. It should contain
"field1" and "field2".

3. Select "field1" and paste to the expression box, select "*" and then
select "field2". The experession will look like this "field1*field2". Once
you close the expression box the expression will look like this
"=field1*field2" in the "ControlSource" field.  Copy this expression to the
Events tab "Before Update" and "After Update" Properties fields.

4. In order to lock your text box so no one will modify it, go to
"properties" on the text box that contains your formula and then to the
"Data" tab and select the locked field "Yes"

Tom