Atlas Steel Company has two departments, Casting and Rolling. In the Rolling Department, ingots from the Casting Department are rolled into steel sheet. The Rolling Department received 86,200 tons from the Casting Department. During the period, the Rolling Department completed 83,580 tons, including 4,150 tons of work in process at the beginning of the period. The ending work in process inventory was 6,770 tons.How many tons were started and completed during the period?