$@Shun$~
`a) -7/2 + (-2/3) + (-3/5)`
`= -25/6 + (-3/5)`
`= -(125)/30 - 18/30`
`=-143/30`
`b) (-1/4 + 1/5) : (49/48 - 1,25)`
`= (-1/20) : (-11/48)`
`= (-1/20) . (48/-11)`
`= 12/55`
`c) 2/7 - 24/12 : 3/5`
`= 2/7 - 10/3`
`= 6/21 - 70/21`
`= -64/21`
`d) -5/7 + 1/7 . (3/4 - 5/1)`
`= -5/7 + 1/7 . (-17/4)`
`= -5/7 + (-17/28)`
`= -20/28 - 17/28`
`= -37/28`
`e) 7/8 : (2/9 - 1/8) + 7/8 : (1/36 - 5/1)`
`= 7/8 : 7/72 + 7/8 : (-179/36)`
`= 7/8 : [7/72 + (-179/36)]`
`= 7/8 : (-39/8)`
`= 7/8 . (8/-39)`
`= -7/39`
