a) \( -5,75 + 3,24 = -2,51 \)
б) \( 6,38 - 2,47 = 3,91 \)
в) \( -(\frac{3}{8} - \frac{1}{4}) = -(\frac{3}{8} - \frac{2}{8}) = -\frac{1}{8} \)