a) $$\frac{16}{23} + \frac{12}{23} - \frac{3}{23} = \frac{16+12-3}{23} = \frac{25}{23} = 1 \frac{2}{23}$$
Ответ: $$1 \frac{2}{23}$$
б) $$2 \frac{5}{11} + 6 \frac{7}{11} = (2+6) + (\frac{5}{11} + \frac{7}{11}) = 8 + \frac{12}{11} = 8 + 1 \frac{1}{11} = 9 \frac{1}{11}$$
Ответ: $$9 \frac{1}{11}$$
в) $$7 - 4\frac{4}{5} = 6\frac{5}{5} - 4\frac{4}{5} = (6-4) + (\frac{5}{5} - \frac{4}{5}) = 2 + \frac{1}{5} = 2\frac{1}{5}$$
Ответ: $$2\frac{1}{5}$$
г) $$5\frac{4}{13} - 3\frac{9}{13} = 4\frac{17}{13} - 3\frac{9}{13} = (4-3) + (\frac{17}{13} - \frac{9}{13}) = 1 + \frac{8}{13} = 1\frac{8}{13}$$
Ответ: $$1\frac{8}{13}$$