`A = (1 - 1/2) xx (1 - 1/3) xx (1-1/4) xx (1 - 1/5)`
`A= 1/2 xx 2/3 xx 3/4 xx 4/5`
`A= (1xx 2xx3xx4)/(2xx3xx4xx5) `
`A =1/5`
````
`B= (1-\frac{3}{4})xx(1-3/7)xx(1-3/10)xx(1-3/13)xx(1-3/16)×(1-3/18)`
`B = 1/4 xx 4/7 xx 7/10 xx 10/13 xx 13/16 xx 15/18`
`B = (1xx4xx7xx10xx13xx15)/(4xx7xx10xx13xx16xx18)`
`B = (1xx15)/(16xx18)`
`B = 5/96`
````
`C = (1-2/5)xx(1-2/7)xx(1-2/11)xx(1-2/13)xx(1-2/15)`
`C = 3/5 xx5/7 xx9/11 xx 11/13 xx 13/15`
`C = (3xx5xx9xx11xx13)/(5xx7xx11xx13xx15) `
`C = (3xx9)/(7xx15)`
`C = 9/35`
````
`D = 2000/2001xx2002/2003xx2001/2002xx2003/2004xx2006/200 `
`D = (2000xx2002xx2001xx 2003xx2006)/(2001xx2003xx2002xx2004xx2000) `
`D= 2006/2004=1003/1002`