Accumulating amounts into a balance

[chamdan]

How can one update a balance such as:

Opening Balance Debit Credit New Balance
$200 $100 -50 $50

When I need to post my new Balance will do the calculation such as the opening balance will be added to the New Balance and then move the New Balance to the opening Balance and "$0.00" the New Balance and the Debit and Credit.

Hope this is clear?

Can it be done through a VBA if yes, can any one show me how?

Thanks for your help in advance.