98+998+9998+...+99...9(100个9）8
=(100-2)+(1000-2)+(10000-2)+...+(100...(100个0)-2)
=111...(99个1)00-200
=111...(97个1)0900
98+998+9998+...+99...9(100个9）8 =
98+998+9998+...+99...9(100个9）8
=(100-2)+(1000-2)+(10000-2)+...+(100...(100个0)-2)
=111...(99个1)00-200
=111...(97个1)0900