2. Выполнить действия с обыкновенными дробями: a) 5 +3 1 1 8 3) :4 15 13 3 5) 2 +8 и) 3:-2 3 5 π) 2₄ +37 4 2 -4- 1 3 7 4)2533 p) - 43 +7 Ⅲ)-3/23 1 5

а) \(\frac{1}{5} + \frac{1}{3} = \frac{3}{15} + \frac{5}{15} = \frac{3+5}{15} = \frac{8}{15}\)

б) \(\frac{1}{2} + \frac{3}{8} = \frac{4}{8} + \frac{3}{8} = \frac{4+3}{8} = \frac{7}{8}\)

з) \(\frac{8}{15} : 4 = \frac{8}{15} \cdot \frac{1}{4} = \frac{8 \cdot 1}{15 \cdot 4} = \frac{8}{60} = \frac{2}{15}\)

и) \(3 : \frac{3}{2} = 3 \cdot \frac{2}{3} = \frac{3 \cdot 2}{3} = \frac{6}{3} = 2\)

п) \(2\frac{3}{4} + 3\frac{5}{7} = \frac{11}{4} + \frac{26}{7} = \frac{11 \cdot 7}{4 \cdot 7} + \frac{26 \cdot 4}{7 \cdot 4} = \frac{77}{28} + \frac{104}{28} = \frac{77 + 104}{28} = \frac{181}{28} = 6\frac{13}{28}\)

р) \(-4\frac{2}{3} + 7\frac{1}{2} = -\frac{14}{3} + \frac{15}{2} = -\frac{14 \cdot 2}{3 \cdot 2} + \frac{15 \cdot 3}{2 \cdot 3} = -\frac{28}{6} + \frac{45}{6} = \frac{-28 + 45}{6} = \frac{17}{6} = 2\frac{5}{6}\)

ч) \(2\frac{3}{4} \cdot 5\frac{7}{33} = \frac{11}{4} \cdot \frac{172}{33} = \frac{11 \cdot 172}{4 \cdot 33} = \frac{1892}{132} = \frac{473}{33} = 14\frac{11}{33} = 14 \frac{1}{3}\)

ш) \(-3\frac{1}{2} \cdot 2\frac{2}{5} = -\frac{7}{2} \cdot \frac{12}{5} = -\frac{7 \cdot 12}{2 \cdot 5} = -\frac{84}{10} = -8.4\)