1/3-1/6-1/12-1/24-1/48
=1/3-(1/3-1/6)-(1/6-1/12)-(1/12-1/24)-)1/24-1/48)
=1/3-1/3+1/6-1/6+1/12-1/12+1/24-1/24+1/48
=1/48