999…9(1988个9)*999…9(1988个9)+1999…9(1988个9)=?
问题描述：
999…9(1988个9)*999…9(1988个9)+1999…9(1988个9)=?
答
=[1000...000(1988个0)-1]*[1000...000(1988个0)-1]+[2000...000(1988个0)-1]=1000...000(3976个0)-2*[1000...000(1988个0)-1]+1+2*[1000...000(1988个0)]-1=1000...000(3976个0)