Реши примеры с 31 по 38

31. $$\frac{8}{21} \cdot \frac{16}{27} - \frac{3}{14} = \frac{8 \cdot 16}{21 \cdot 27} - \frac{3}{14} = \frac{128}{567} - \frac{3}{14} = \frac{128 \cdot 2}{567 \cdot 2} - \frac{3 \cdot 81}{14 \cdot 81} = \frac{256}{1134} - \frac{243}{1134} = \frac{256 - 243}{1134} = \frac{13}{1134}$$ 32. $$(\frac{2}{3} - \frac{4}{9}) \cdot \frac{3}{8} = (\frac{2 \cdot 3}{3 \cdot 3} - \frac{4}{9}) \cdot \frac{3}{8} = (\frac{6}{9} - \frac{4}{9}) \cdot \frac{3}{8} = \frac{2}{9} \cdot \frac{3}{8} = \frac{2 \cdot 3}{9 \cdot 8} = \frac{6}{72} = \frac{1}{12}$$ 33. $$\frac{11}{8} - \frac{15}{16} : \frac{25}{28} = \frac{11}{8} - \frac{15}{16} \cdot \frac{28}{25} = \frac{11}{8} - \frac{15 \cdot 28}{16 \cdot 25} = \frac{11}{8} - \frac{3 \cdot 7}{4 \cdot 5} = \frac{11}{8} - \frac{21}{20} = \frac{11 \cdot 5}{8 \cdot 5} - \frac{21 \cdot 2}{20 \cdot 2} = \frac{55}{40} - \frac{42}{40} = \frac{55 - 42}{40} = \frac{13}{40}$$ 34. $$\frac{4}{5} - \frac{5}{24} : \frac{25}{32} = \frac{4}{5} - \frac{5}{24} \cdot \frac{32}{25} = \frac{4}{5} - \frac{5 \cdot 32}{24 \cdot 25} = \frac{4}{5} - \frac{1 \cdot 4}{3 \cdot 5} = \frac{4}{5} - \frac{4}{15} = \frac{4 \cdot 3}{5 \cdot 3} - \frac{4}{15} = \frac{12}{15} - \frac{4}{15} = \frac{12 - 4}{15} = \frac{8}{15}$$ 35. $$\frac{5}{12} \cdot (\frac{1}{5} + \frac{3}{25}) = \frac{5}{12} \cdot (\frac{1 \cdot 5}{5 \cdot 5} + \frac{3}{25}) = \frac{5}{12} \cdot (\frac{5}{25} + \frac{3}{25}) = \frac{5}{12} \cdot \frac{8}{25} = \frac{5 \cdot 8}{12 \cdot 25} = \frac{1 \cdot 2}{3 \cdot 5} = \frac{2}{15}$$ 36. $$\frac{8}{9} - \frac{8}{15} \cdot \frac{5}{6} = \frac{8}{9} - \frac{8 \cdot 5}{15 \cdot 6} = \frac{8}{9} - \frac{8 \cdot 1}{3 \cdot 6} = \frac{8}{9} - \frac{8}{18} = \frac{8 \cdot 2}{9 \cdot 2} - \frac{8}{18} = \frac{16}{18} - \frac{8}{18} = \frac{16 - 8}{18} = \frac{8}{18} = \frac{4}{9}$$ 37. $$\frac{3}{16} \cdot (\frac{4}{5} + \frac{8}{15}) = \frac{3}{16} \cdot (\frac{4 \cdot 3}{5 \cdot 3} + \frac{8}{15}) = \frac{3}{16} \cdot (\frac{12}{15} + \frac{8}{15}) = \frac{3}{16} \cdot \frac{20}{15} = \frac{3 \cdot 20}{16 \cdot 15} = \frac{1 \cdot 5}{4 \cdot 5} = \frac{1}{4}$$ 38. $$\frac{18}{35} : 12 + \frac{1}{10} = \frac{18}{35} : \frac{12}{1} + \frac{1}{10} = \frac{18}{35} \cdot \frac{1}{12} + \frac{1}{10} = \frac{18}{35 \cdot 12} + \frac{1}{10} = \frac{3}{35 \cdot 2} + \frac{1}{10} = \frac{3}{70} + \frac{1}{10} = \frac{3}{70} + \frac{1 \cdot 7}{10 \cdot 7} = \frac{3}{70} + \frac{7}{70} = \frac{3 + 7}{70} = \frac{10}{70} = \frac{1}{7}$$