`( - 1/2 ) + ( - 1/9 ) - ( - 3/5 ) + 1/2006 - ( - 2/7 ) - 7/18 + 4/35`
`= ( - 1/2 ) - 1/9 + 3/5 + 1/2006 + 2/7 - 7/18 + 4/35`
`= [ ( - 1/2 ) - 1/9 - 7/18 ] + [ 3/5 + 2/7 + 4/35 ] + 1/2006`
`= [ ( - 9/18 ) - 2/18 - 7/18 ] + [ 21/35 + 10/35 + 4/35 ] + 1/2006`
`= [ ( - 11 )/18 - 7/18 ] + [ 31/35 + 4/35 ] + 1/2006`
`= ( - 1 ) + 1 + 1/2006`
`= 0 + 1/2006`
`= 1/2006`