Kew Company uses the weighted-average method in its process costing system. The company had 3,000 units in work in process at April 1 that were 60% complete with respect to conversion cost. During April, 10,000 units were completed. At April 30, 4,000 units remained in work in process and they were 40% complete with respect to conversion cost. Direct materials are added at the beginning of the process. How many units were started during April?