`a) \frac{-3}{7} . \frac{12}{-13} . (\frac{-14}{15})`
`=[ \frac{-3}{7} . (\frac{-14}{15}) ]. \frac{12}{-13}`
`= 2/5 . \frac{12}{-13}`
`= -24/65`
`b) 5/8 - 3/8 : (\frac{-3}{4}) - 1/4 . 0`
`= 5/8 - 3/8 . (\frac{-4}{3}) - 0`
`= 5/8 - (-1/2) - 0`
`= 9/8 - 0`
`= 9/8`
`c) (-1 1/2) : \frac{3}{-4} . ( -4 1/2)`
`= (-3/2) . (-\frac{-4}{3}) . (-9/2)`
`= 2 . (-9/2)`
`= -4/9`
`d) 2 1/3 . (-3 1/4) . (-2,5)`
`= 7/3 . ( -13/4) . (-5/2)`
`= -91/12 . (-5/2)`
`= 455/24`
`e) ( \frac{-5}{6} + 2/5) : 3/8 + (4/5- 11/30) : 3/8`
`= -13/30 . 8/3 + 13/30 . 8/3`
`= 8/3 . ( -13/30 + 13/30)`
`= 8/3 . 0`
`= 0`
`f) 5/9 : (1/11 - 5/22) : (1/11 - 2/3)`
`= 5/9 : (-3/22) : (-19/33)`
`= -110/27 : (-19/33)`
`=1210/171`
