`1/2 + 5/6 + 11/12 + 19/20 + 29/30 + 41/42`
`= (1-1/2) + ( 1 - 1/6) + ( 1 - 1/12) + ( 1- 1/20) + (1-1/30) + ( 1-1/42)`
`= 6- ( 1/2 + 1/6 + 1/12 + 1/20 + 1/30+ 1/42)`
`= 6- (1/1.2 + 1/2.3 + 1/3.4 + 1/4.5 + 1/5.6 + 1/6.7)`
`=6- ( 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + 1/5 - 1/6 + 1/6-1/7)`
`= 6- ( 1- 1/7)`
`= 6 - 6/7`
`= 36/7`
