`\text{a)}`
`25% - 1 1/2 + 0,5 . 12/5`
`= 1/4 - 3/2 + 1/2 . 12/5`
`= 1/4 - 6/4 + 6/5`
`= -5/4 + 6/5`
`= -25/20 + 24/20`
`= -1/20`
`\text{b)}`
`|{-7}/9| + (-1/3)^2 - (2016)^0`
`= 7/9 + 1/9 - 1`
`= 7/9 +1/9 - 9/9`
`= -1/9`
`\text{c)}`
`({-3}/11 : 5/9 + {-8}/11 : 5/9 ) . {|-5|}/3`
`= ( {-3}/11 . 9/5 + {-8}/11 . 9/5 ) . 5/3`
`= 9/5({-3}/11 - 8/11 ) . 5/3`
`= {-9}/5 . 5/3`
`= -3`