$$\frac{4}{13} + \frac{3}{13} = \frac{4+3}{13} = \frac{7}{13}$$
Ответ: $$\frac{7}{13}$$
$$\frac{7}{11} - \frac{1}{11} = \frac{7-1}{11} = \frac{6}{11}$$
Ответ: $$\frac{6}{11}$$
$$4\frac{3}{9} + 2\frac{1}{9} = (4 + 2) + (\frac{3}{9} + \frac{1}{9}) = 6 + \frac{4}{9} = 6\frac{4}{9}$$
Ответ: $$6\frac{4}{9}$$
$$8\frac{4}{5} - 7\frac{2}{5} = (8 - 7) + (\frac{4}{5} - \frac{2}{5}) = 1 + \frac{2}{5} = 1\frac{2}{5}$$
Ответ: $$1\frac{2}{5}$$
$$3\frac{9}{16} + 2\frac{3}{16} = (3 + 2) + (\frac{9}{16} + \frac{3}{16}) = 5 + \frac{12}{16} = 5 + \frac{3}{4} = 5\frac{3}{4}$$
Ответ: $$5\frac{3}{4}$$
$$5\frac{6}{13} - 3\frac{1}{13} = (5 - 3) + (\frac{6}{13} - \frac{1}{13}) = 2 + \frac{5}{13} = 2\frac{5}{13}$$
Ответ: $$2\frac{5}{13}$$
$$\frac{9}{22} \cdot \frac{11}{27} = \frac{9 \cdot 11}{22 \cdot 27} = \frac{1 \cdot 1}{2 \cdot 3} = \frac{1}{6}$$
Ответ: $$\frac{1}{6}$$
$$\frac{4}{27} : \frac{20}{81} = \frac{4}{27} \cdot \frac{81}{20} = \frac{4 \cdot 81}{27 \cdot 20} = \frac{1 \cdot 3}{1 \cdot 5} = \frac{3}{5}$$
Ответ: $$\frac{3}{5}$$