Решение:
- \( 2 \frac{3}{5} = \frac{2 \times 5 + 3}{5} = \frac{10 + 3}{5} = \frac{13}{5} \)
- \( 5 \frac{5}{3} = \frac{5 \times 3 + 5}{3} = \frac{15 + 5}{3} = \frac{20}{3} \)
- \( 12 \frac{7}{10} = \frac{12 \times 10 + 7}{10} = \frac{120 + 7}{10} = \frac{127}{10} \)
- \( 2 \frac{18}{23} = \frac{2 \times 23 + 18}{23} = \frac{46 + 18}{23} = \frac{64}{23} \)
Ответ: 1) \( \frac{13}{5} \); 2) \( \frac{20}{3} \); 3) \( \frac{127}{10} \); 4) \( \frac{64}{23} \).