How to calculate cost of good sold in access vba

[tomy]

hi - I need some basic help .I have a table with three field , Sales, Cgs and Average profit. I want to create a form based on that table .the problem is i dont know how to calculate the cost of good sold using access form .I need to calculate cgs but the situation is
I have to enter cost per item from purchase once a week and enter total sale every day.How do i multipy the quantity of sale with cost per item ?
if some someone help me I shall be grateful to you.

 

[vbaInet]

How do i multipy the quantity of sale with cost per item ?

Create a query that will pull records from the tables that contain Quantity and Cost of each item, [Qty]*[Cost]