Variables in the solution mix, which is often called the basis in LP terminology, are referred to as basic variables. In this example, the basic variables are S1 and S2. Variables not in the solution mix—or basis—(X1 and X2, in this case) are Cj Zj : This number represents the net profit (that is, the profit gained minus the profit given up), which will result from introducing one unit of each product (variable) into the solution. It is not calculated for the quantity column. To compute these numbers, we simply subtract the Zj total from the Cj value at the very top of each variable’s column. The calculations for the net profit per unit (Cj Zj ) row in this example are as follows: