作业帮 > 数学 > 作业

计算:999...9(n个9)*999...9(n个9)+1999...9(n个9)

来源:学生作业帮 编辑:灵鹊做题网作业帮 分类:数学作业 时间:2024/04/29 11:19:22
计算:999...9(n个9)*999...9(n个9)+1999...9(n个9)
计算:999...9(n个9)*999...9(n个9)+1999...9(n个9)
999...9(n个9)*999...9(n个9)+1999...9(n个9)
=999...9(n个9)*【1000...0(n个0)-1】+1999...9(n个9)
=999...9000...0(n个9,n个0)-999...9(n个9)+1999...9(n个9)
=999...9000...0(n个9,n个0)+【1999...9(n个9)-999...9(n个9)】
=999...9000...0(n个9,n个0)+1000...0(n个0)
=1000...0(2n个0)