4×3.09×0.25＝﹙4×0.25﹚×3.09＝1×3.09＝3.09满意请采纳
4×3.09×0.25=(4×0.25)×3.09=1×3.09=3.09
4×0.25＝10再乘3.09＝30.9就用一下乘法交换律
0.25×4×3.09＝1×3.09＝3.09望采纳。
＝4×0.25×3.09＝3.094×0.25＝1
