№2. Выполни действия: 1) \frac{6}{28} + \frac{12}{20} - \frac{15}{28}; 2) 3\frac{4}{37} - 1\frac{15}{37} + 5\frac{6}{37}; 3) 1-\frac{21}{44}; 4) 10\frac{8}{17}-6\frac{3}{17}; 5) \frac{27}{24}:\frac{18}{51}; 6) \frac{24}{32}:\frac{16}{24}

№2. Выполни действия:

1) \frac{6}{28} + \frac{12}{20} - \frac{15}{28} = \frac{6}{28} - \frac{15}{28} + \frac{12}{20} = \frac{6-15}{28} + \frac{12}{20} = \frac{-9}{28} + \frac{12}{20} = \frac{-9}{28} + \frac{3}{5} = \frac{-9 \cdot 5}{28 \cdot 5} + \frac{3 \cdot 28}{5 \cdot 28} = \frac{-45}{140} + \frac{84}{140} = \frac{-45+84}{140} = \frac{39}{140}.

2) 3\frac{4}{37} - 1\frac{15}{37} + 5\frac{6}{37} = 3\frac{4}{37} + 5\frac{6}{37} - 1\frac{15}{37} = (3+5) + (\frac{4}{37} + \frac{6}{37}) - 1\frac{15}{37} = 8 + \frac{4+6}{37} - 1\frac{15}{37} = 8 + \frac{10}{37} - 1\frac{15}{37} = 8\frac{10}{37} - 1\frac{15}{37} = (8-1) + (\frac{10}{37} - \frac{15}{37}) = 7 + \frac{10-15}{37} = 7 + \frac{-5}{37} = 7 - \frac{5}{37} = 6\frac{37}{37} - \frac{5}{37} = 6\frac{37-5}{37} = 6\frac{32}{37}.

3) 1-\frac{21}{44} = \frac{44}{44} - \frac{21}{44} = \frac{44-21}{44} = \frac{23}{44}.

4) 10\frac{8}{17}-6\frac{3}{17} = (10-6) + (\frac{8}{17} - \frac{3}{17}) = 4 + \frac{8-3}{17} = 4 + \frac{5}{17} = 4\frac{5}{17}.

5) \frac{27}{24}:\frac{18}{51} = \frac{27}{24} \cdot \frac{51}{18} = \frac{27 \cdot 51}{24 \cdot 18} = \frac{3 \cdot 9 \cdot 3 \cdot 17}{3 \cdot 8 \cdot 2 \cdot 9} = \frac{3 \cdot 17}{8 \cdot 2} = \frac{51}{16} = 3\frac{3}{16}.

6) \frac{24}{32}:\frac{16}{24} = \frac{24}{32} \cdot \frac{24}{16} = \frac{24 \cdot 24}{32 \cdot 16} = \frac{8 \cdot 3 \cdot 8 \cdot 3}{8 \cdot 4 \cdot 8 \cdot 2} = \frac{3 \cdot 3}{4 \cdot 2} = \frac{9}{8} = 1\frac{1}{8}.

Ответ: 1) \frac{39}{140}; 2) 6\frac{32}{37}; 3) \frac{23}{44}; 4) 4\frac{5}{17}; 5) 3\frac{3}{16}; 6) 1\frac{1}{8}