` -9/12 + 7/12 - 1/12 `
` = -1/4 `
` -15/40 - 3/8 : \frac{-7}{2} `
` = -15/40 - \frac{-3}{28} `
` = -15/56 `
` 5/9 + 4/9 : (-4) - 7/15 `
` = 5/9 + \frac{-1}{9} - 7/15 `
` = 4/9 - 7/15 `
` = -1/45 `
` (75% - 1/16) + (-1 3/4) . 1/7 `
` = (3/4 - 1/16) + \frac{-7}{4} . 1/7 `
` = 11/16 + \frac{-1}{4} `
` = 7/16 `
` -3/25 - 4/25 + \frac{-8}{25} `
` = \frac{-15}{25} = -3/5 `
` 9/11 - 2/11 . \frac{-3}{5} `
` = 9/11 - \frac{-6}{55} `
` = 51/55 `
` -1,6 : (1+8/12) `
` = -8/5 : 5/3 `
` = -24/25 `