(х-80)÷40=640 (х-80)×40=640 х-80=640÷40 х-80=640×40
1)х-80:40=640 2)х-80*40=640. 3) х=640:40+80 х=640+80*40. х=640+80:40. х=16+80 х=640+3200. х= 640+2. х=96 х=3840 х= 642 4) х=640*40+80 х=25600+80 х=25680