657450:90+83*600 (612237-240037):40 70*(100100-99800)

657450:90+83*600=57105 657450:90=7305 83*600=49800 7305+49800=57105 (612237-240037):40=9305 612237-240037=372200 372200:40=9305 70*(100100-99800)=21000 100100-99800=300 70*300=21000