The largest difference in the tableau above is 5 corresponding to the third column. Hence we use the smallest cost in third column, namely 2, to empty a warehouse or completely fill a market demand. 2 denotes the unit cost of shipping widgits from w1 to w3 ;since w3 only needs 20 tons of the possible 40 tons in w1, we ship 20 tons of widgits from w1 to w3 and therefore fulfill the demand of M3. We then adjust the supply of w1 and the demand of M3 accordingly, i.e., after such a shipment, the current supply of is 40 – 20 = 20 and the current demand of M3 is 20 – 20 = 0. The entire transaction is recorded as follows: