`(1-1/2)xx(1-1/3) xx (1-1/4) xx (1-1/5) xx (1-1/6) xx(1-1/7)`
`=(2/2-1/2)xx(3/3-1/3)xx(4/4-1/4)xx(5/5-1/5)xx(6/6-1/6)xx(7/7-1/7)`
`=1/2 xx 2/3 xx 3/4 xx 4/5 xx 5/6 xx 6/7`
`=(1xx2xx3xx4xx5xx6)/(2xx3xx4xx5xx6xx7)`
`=1/7`
\(=\dfrac{1}{2}.\dfrac{2}{3}.\dfrac{3}{4}.\dfrac{4}{5}.\dfrac{5}{6}.\dfrac{6}{7}=\dfrac{1.2.3.4.5.6}{2.3.4.5.6.7}=\dfrac{1}{7}\)
`=1/2.2/3.3/4.4/5.5/6.6/7`
`=(1.2.3.4.5.6)/(2.3.4.5.6.7)`
=1/7`