3) 15 -4 2 3) -4,1+(-60+2): 3 5) (2.75+1)+(-2)+(-5,8+1). г) T PLA A S

а) \[ \frac{7}{2} + (-0.6) + (-5\frac{3}{4}) = 3.5 - 0.6 - 5.75 = 2.9 - 5.75 = -2.85 \]

б) \[ (2.75 + \frac{1}{5}) - (-\frac{7}{12}) = 2.75 + 0.2 + \frac{7}{12} = 2.95 + \frac{7}{12} = \frac{295}{100} + \frac{7}{12} = \frac{59}{20} + \frac{7}{12} = \frac{59 \cdot 3 + 7 \cdot 5}{60} = \frac{177 + 35}{60} = \frac{212}{60} = \frac{53}{15} = 3\frac{8}{15} \]

в) \[ -4.1 + (-6\frac{17}{60} + 2\frac{5}{12}) = -4.1 + (-6 - \frac{17}{60} + 2 + \frac{5}{12}) = -4.1 + (-4 - \frac{17}{60} + \frac{25}{60}) = -4.1 + (-4 + \frac{8}{60}) = -4.1 - 4 + \frac{2}{15} = -8.1 + \frac{2}{15} = -8\frac{1}{10} + \frac{2}{15} = -8\frac{3}{30} + \frac{4}{30} = -8\frac{1}{30} \]

г) \[ \frac{1}{4} + (-5.8 + \frac{3}{4}) = 0.25 - 5.8 + 0.75 = 1 - 5.8 = -4.8 \]