2. Вычисли: a) -3,15 - (-4 1/2 + 3 3/4); б) 1,843 - (8,74 - 3,79); в) 5 7/17 - (2 1/2 - 10/17).

a) \[ -3,15 - (-4\frac{1}{2} + 3\frac{3}{4}) = -3,15 - (-4,5 + 3,75) = -3,15 - (-0,75) = -3,15 + 0,75 = -2,4 \] б) \[ 1,843 - (8,74 - 3,79) = 1,843 - 4,95 = -3,107 \] в) \[ 5\frac{7}{17} - (2\frac{1}{2} - \frac{10}{17}) = 5\frac{7}{17} - (2,5 - \frac{10}{17}) = 5\frac{7}{17} - (\frac{5}{2} - \frac{10}{17}) = \frac{92}{17} - \frac{85}{34} + \frac{20}{34} = \frac{184}{34} - \frac{85}{34} + \frac{20}{34} = \frac{119}{34} = 3\frac{17}{34} = 3\frac{1}{2} = 3,5 \]