=4/3-(1/3+1/4)+(1/4+1/5)-(1/5+1/6)+(1/6+1/7)-(1/7+1/8)=4/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7-1/7-1/8=1-(1/4-1/4)+(1/5-1/5)-(1/6-1/6)+(1/7-1/7)-1/8=1-1/8=7/8
