求19+199+1999+19999·······+1999···99(2002个9)的简便计算
问题描述:
求19+199+1999+19999·······+1999···99(2002个9)的简便计算
答
19+199+1999+19999·······+1999···99(2002个9)
=20-1+200-1+2000-1+.+20000..0(2002个0)-1
=2222222.22(2003个2)-2002
=2222.222220220 (共2003位)