577.44≈5805.83≈5.8538.5≈540（5.83-0.56）=5.25所以577.44×5.83-583.5×（5.83-0.56）≈580×5.8-540×5.25＝580×5.8-（580-40）×5.25展开合并公因式以后=580×（5.8-5.25）+40×5.25＝580×0.55+40×5.25=529
