`a, 2/7 + 5/7 . 14/25 = 2/7 + 2/5 = 24/35`
`b, 4/7 : (2/5 . 4/7) = 4/7 : 8/35 = 5/2`
`c, 6/7 + 5/7 : 5 - 8/9 = 6/7 + 1/7 - 8/9 = 1 - 8/9 = 1/9`
`d, 5/7 . 2/11 + 5/7 . 9/11 = 5/7 . (2/11 + 9/11) = 5/7 . 1 = 5/7`
`e, 1/2 . (2/9 + 3/7 - 5/27) = 1/2 . 88/189 = 44/189`
`f, 1/3 . 5/7 - 7/27 . 36/14 = 5/21 - 2/3 = -3/7`
`g, -5/9 + 8/15 + \frac{-2}{11} + \frac{4}{-9} + 7/15`
`= (-5/9 + \frac{4}{-9}) + (8/15 + 7/15) + \frac{-2}{11} = -1 + 1 + \frac{-2}{11} = \frac{-2}{11}`
`h, 7/19 . 8/11 + 3/11 . 7/19 + \frac{-12}{19}`
`= 7/19 . (8/11 + 3/11) + \frac{-12}{19} = 7/19 . 1 + \frac{-12}{19} = 1`
`i, 5/9 . 7/13 + 5/9 . 9/13 - 5/9 . 3/13`
`= 5/9 . (7/13 + 9/13 - 3/13) = 5/9 . 1 = 5/9`
