用简便方法计算 0.125×2.6×0.8 46×0.77+54×0.77 =0.125×0.8×2.6 =(46+54)×0.77 =0.1×2.6 =100×0.77 =0.26 =77 5.78×101 2.5×204 =5.78×(100+1) =2.5×(200+4) =5.78×100+5.78×1 =2.5×200+2.5×4 =578+5.78 =500+10 =583.78 =510 3.2×125 (125-40)×0.8 =0.4×(8×125) =125×0.8—40×0.8 =0.4×1000 =100-32 =400 =68