来自顾训穰的问题
数学乘法巧算,急99.9(2003个“9”)*99.9(2003个“9”)+199.9(2003个“9”),结尾有多少个“0”?
数学乘法巧算,急
99.9(2003个“9”)*99.9(2003个“9”)+199.9(2003个“9”),结尾有多少个“0”?
1回答
2020-06-05 16:07
数学乘法巧算,急99.9(2003个“9”)*99.9(2003个“9”)+199.9(2003个“9”),结尾有多少个“0”?
数学乘法巧算,急
99.9(2003个“9”)*99.9(2003个“9”)+199.9(2003个“9”),结尾有多少个“0”?
原式=
(100...00(2003个0)-1)*999..99(2003个9)+1999...9(2003个9)
=999...900..00(2003个9,2003个0)-999..9(2003个9)+1999..9(2003个9)
=999...900..00(2003个9,2003个0+1000..0(2003个0)
所以有2003个0