I've figured it out. On the Save Record macro button I added SQL to update the inventory table and worked.

Thanks anyway and have a great day!

I have an order table and an inventory table. I have a form with combo and text boxes to add new orders to order table. I want to be able to reduce the # of stock in inventory table by number of items entered in order form box.
In other words, when I input a value in QuantityOrdered and save the record to the tblOrders, I would like the value in StockOnHand in the tblInventory to be [StockOnHand] minus [QuantityOrdered]