12+56+1112+1920+…+98999900=______.

12+56+1112+1920+…+98999900=______.

12+56+112+1920+...+9899900=(1-12)+(1-112)+(1-112)+(1-120)+...+(1-19900)=99-(12+16+120+130+...+19900)=99-(1-12+12-13+13-14+14+15-16+...+199-(1-1100)=99-(1-1100)=99-1+1100=98+0.01=98.01.