21770 - 12691 = 21779 - 12700 = 9079 13541 - 7394 = 13547 - 7400 = 6147 150683 - 129993 = 150690 - 130000 = 20690 16940 - 6984 = 16956 - 7000 = 9956 6597 + 2265 = 6600 + 2262 = 8862 1837 + 2298 = 1835 + 2300 = 4135 5138 - 1335 = 5103 - 1300 = 3803 37574 + 19999 = 37573 + 20000 = 57573