The Rose Petal Lotion Company filling department began the period with 2,300 ounces of work in process inventory that was 70% complete. During the period they completed 46,500 ounces of production. The ending work in process inventory was 1,800 ounces at 25% complete. To calculate the total equivalent units of direct materials needed if materials are added at the beginning, we take the units completed (46,500 ounces) plus the closing work in process inventory (1,800 ounces) which equals the total units introduced during the period.