来自孙益辉的问题
1-2/1-4/1.-64/1-128/1-256/1
1-2/1-4/1.-64/1-128/1-256/1


1-2/1-4/1.-64/1-128/1-256/1
1-2/1-4/1.-64/1-128/1-256/1
1-2/1-4/1.-64/1-128/1-256/1=256/1
1-(1-1/2)-(1/2-1/4).-(1/64-1/128)-(1/128-1/256)
=1-1+1/2-1/2+1/4-4/1.1/64-1/64+1/128-1/128+1/256
=1/256