How to Match Goods received note value Vs Purchases order value in Ms Access

Dear All;

See how you can assist on the issue below:

Background

We place purchases orders to vendors every month, now it is the policy of management to match the goods received note with the purchase order so that in the event where some material are not received as per purchase order management can easily track that information. Therefore , I'm required to create a VBA code to do the matching so that those unfinished  purchase orders can be properly managed.

Here I want to be matching the Purchase order value vs goods received note value so that those that completely  received should show zero and those not finished show the remaining balance any Idea?

Regards

Chris