2.(1)(50+40)*4=360km (2)(50+40)*3.5+45=360km
(3)(50+40)*4.5-45=360km (4)20*2/(50-40)=4小时 (50+40)*4=360km
3.(12+8)*3/12=5天
拓展应用:(102-60)/(5-2)=14千克 60-14*2=32千克
2.(1)(50+40)*4=360km (2)(50+40)*3.5+45=360km
(3)(50+40)*4.5-45=360km (4)20*2/(50-40)=4小时 (50+40)*4=360km
3.(12+8)*3/12=5天
拓展应用:(102-60)/(5-2)=14千克 60-14*2=32千克