(1)3.2+7.5×0.5, =3.2+3.75, =6.95; (2)0.73×50×0.4, =0.73×(50×0.4), =0.73×20, =14.6; (3)0.9×[13-(4.75+5.25)], =0.9×[13-10], =0.9×3, =2.7; (4)2.78+59.8+1.22, =(2.78+1.22)+59.8, =4+59.8, =63.8; (5)9.63×2.5+6.37×2.5, =(9.63+6.37)×2.5, =16×2.5, =40; (6)(12-1.5÷0.5)×4.2, =(12-3)×4.2, =9×4.2, =37.8. |