=80+0.5+80+0.7+80-0.2+80-1.1+80+0.8+80-0.5+80+0.2+80+1.01=80*8+0.5+0.7-0.2-1.1+0.8-0.5+0.2+1.01=640+0.7-1.1+0.8+1.01=640-1.1+1.01+0.7+0.8=640-0.1+0.01+1.5=640+1.41=641.41
