3. Вычислите: 1) 1\(\frac{7}{15} - \frac{4}{25}\) 2) 6\(\frac{3}{4}\) \(\cdot 1\frac{1}{5}\) 3) 3\(\frac{1}{5}\) : 2\(\frac{2}{5}\) 4) \(\(48:45 - \frac{1}{3}\) \(\cdot\) 2\(\frac{3}{11}\) + \(\frac{3}{5}\)\)

Решение:

1. \( 1\frac{7}{15} - \frac{4}{25} = \frac{22}{15} - \frac{4}{25} \). Общий знаменатель для 15 и 25 — 75. \( \frac{22 \times 5}{15 \times 5} - \frac{4 \times 3}{25 \times 3} = \frac{110}{75} - \frac{12}{75} = \frac{98}{75} = 1\frac{23}{75} \)
2. \( 6\frac{3}{4} \cdot 1\frac{1}{5} = \frac{27}{4} \cdot \frac{6}{5} = \frac{27 \times 6}{4 \times 5} = \frac{162}{20} = \frac{81}{10} = 8\frac{1}{10} \)
3. \( 3\frac{1}{5} : 2\frac{2}{5} = \frac{16}{5} : \frac{12}{5} = \frac{16}{5} \times \frac{5}{12} = \frac{16}{12} = \frac{4}{3} = 1\frac{1}{3} \)
4. \(\(48:45 - \frac{1}{3}\) \(\cdot\) 2\(\frac{3}{11}\) + \(\frac{3}{5}\)\) = \(\( \frac{48}{45} - \frac{1}{3}\) \(\cdot\) \(\frac{25}{11}\) + \(\frac{3}{5}\)\) = \(\( \frac{16}{15} - \frac{5}{15}\) \(\cdot\) \(\frac{25}{11}\) + \(\frac{3}{5}\)\) = \(\( \frac{11}{15}\) \(\cdot\) \(\frac{25}{11}\) + \(\frac{3}{5}\)\) = \( \frac{11 \times 25}{15 \times 11} + \frac{3}{5}\) = \( \frac{25}{15} + \frac{3}{5}\) = \( \frac{5}{3} + \frac{3 \times 3}{5 \times 3}\) = \( \frac{5}{3} + \frac{9}{15}\) = \( \frac{5 \times 5}{3 \times 5} + \frac{9}{15}\) = \( \frac{25}{15} + \frac{9}{15}\) = \( \frac{34}{15}\) = 2\(\frac{4}{15}\)

Ответ: 1) \(1\frac{23}{75}\) 2) \(8\frac{1}{10}\) 3) \(1\frac{1}{3}\) 4) \(2\frac{4}{15}\)