I am trying to create a related formula using Power Pivot in Excel. Please create a formula that calculates the following.

There are two tables of data. The first table (Sales Table) has the sales price of various transactions and the product number of what was sold. The second table (Product Key) lists what product each product number represents.

I want to add a column in the Product Ket table that calculates the total sales amount for each product is. I.e., If there are three transactions for product number 4 that equal $549, the formula will automatically add together the transactions and input the data into the Net Sales column in the Product Key table.

Thanks for your help!