1∕1﹡2﹢1∕2﹡3﹢1∕3﹡4﹢1∕4﹡5……﹢1∕98﹡99﹢1∕99﹡100
=1-1/2+(1/2-1/3)+(1/3-1/4)+……+( 1/99-1/100)
=1-1/100
=99/100