2.58X9.9十0.258=2.58x9.9+2.58x0.1=2.58x(9.9+0.1)=2.58x10=25.8
2.58X9.9十0.258=0.258×99+0.258×1=0.258×(99+1) =0.258×1=0.258
你好,解题思路如下