`b, 5 1/6 - 3 2/5`
`= 31/6 - 17/5`
`=53/30`
`----`
`5 1/6 - 3 2/5`
`= 2 (1/6-2/5)`
`=2 (-7/30)`
`=53/30`
`d, 8 2/7 - ( 3 4/9 + 4 2/7)`
`=58/7 - ( 31/9 + 30/7)`
`= 58/7 - 487/63`
`= 5/9`
`-----`
` 8 2/7 - ( 3 4/9 + 4 2/7)`
`= 8 2/7 - 7 (4/9 +2/7)`
`= 8 2/7 - 7 46/63`
`= 1 (2/7 - 46/63)`
`=1 (-4/9)`
`= 5/9`
`