Решение:

a) $$(\frac{4}{9} + \frac{2}{9}) \cdot \frac{9}{13} = \frac{6}{9} \cdot \frac{9}{13} = \frac{2}{3} \cdot \frac{9}{13} = \frac{2 \cdot 3}{13} = \frac{6}{13}$$

б) $$\frac{2}{3} \cdot (\frac{9}{8} - \frac{3}{4}) = \frac{2}{3} \cdot (\frac{9}{8} - \frac{6}{8}) = \frac{2}{3} \cdot \frac{3}{8} = \frac{1}{4}$$

в) $$(\frac{9}{11} - \frac{4}{11}) \cdot \frac{11}{5} = \frac{5}{11} \cdot \frac{11}{5} = 1$$

г) $$2 \cdot \frac{1}{8} + \frac{7}{12} \cdot \frac{3}{7} = \frac{2}{8} + \frac{3}{12} = \frac{1}{4} + \frac{1}{4} = \frac{2}{4} = \frac{1}{2}$$

д) $$(\frac{2}{3})^2 + \frac{13}{21} \cdot \frac{7}{26} - \frac{5}{18} = \frac{4}{9} + \frac{1}{3} \cdot \frac{1}{2} - \frac{5}{18} = \frac{4}{9} + \frac{1}{6} - \frac{5}{18} = \frac{8}{18} + \frac{3}{18} - \frac{5}{18} = \frac{8+3-5}{18} = \frac{6}{18} = \frac{1}{3}$$

е) $$(\frac{3}{7} - \frac{1}{7})^2 \cdot \frac{49}{16} + (\frac{1}{2})^3 = (\frac{2}{7})^2 \cdot \frac{49}{16} + \frac{1}{8} = \frac{4}{49} \cdot \frac{49}{16} + \frac{1}{8} = \frac{1}{4} + \frac{1}{8} = \frac{2}{8} + \frac{1}{8} = \frac{3}{8}$$

Ответ:

• а) $$\frac{6}{13}$$
• б) $$\frac{1}{4}$$
• в) $$1$$
• г) $$\frac{1}{2}$$
• д) $$\frac{1}{3}$$
• е) $$\frac{3}{8}$$