`15 3/13 - (3 4/7 + 8 3/13 )`
`= 15 3/13 - 3 4/7 - 8 3/13 `
`= 15 3/13 - 8 3/13 - 3 4/7`
`= 7 - 3 4/7`
`= 3 3/7`
`(7 4/9 + 4 7/11)- 3 4/9`
`= 7 4/9 + 4 7/11 - 3 4/9`
`= 7 4/9 - 3 4/9 + 4 7/11`
`=4 + 4 7/11`
`= 8 7/11`
`-7/9 . 4/11 + -7/9 . 7/11 + 5 7/9`
`=-7/9(4/11+7/11) + 5 7/9`
`= -7/9 + 5 7/9`
`=5`