Easy Subtraction in fields ?

I have three fields that are named
Deposit Balance Refund


I would like to have the Deposit and Balance fields show the same value when it's entered into the recordset and if a value for Refund is entered, have that amount subtracted from the Balance leaving the Deposit the same.

SQLstring = "Select Deposit, Refund WHERE Refund - Balance"

???

I'd rather do it automatically on the Text_Change Sub when data is entered in the field.

THX in advance.

Text11.Text = Val(Text9.Text) - Val(Text10.Text)

This works but only first two digits, if I use currency format it doesn't.

Anyone know how I can use cents (10.XX) with using number formating in the textbox. If I type in 10.50 the result changes to using only two digits.

THX