1.6. Деление обыкновенных дробей 1) 2/5 : 1/3 = 2) 3/4 : 1/8 = 3) 7/15 : 7/30 = 4) 6 : 6/7 = 5) 6 : 8 = 6) 16/21 : 8 = 7) 5/12 : 3/10 = 8) 1 1/4 : 2 1/2 =

Решение:

1. \( \frac{2}{5} : \frac{1}{3} = \frac{2}{5} \times \frac{3}{1} = \frac{2 \times 3}{5 \times 1} = \frac{6}{5} = 1 \frac{1}{5} \)
2. \( \frac{3}{4} : \frac{1}{8} = \frac{3}{4} \times \frac{8}{1} = \frac{3 \times 8}{4 \times 1} = \frac{24}{4} = 6 \)
3. \( \frac{7}{15} : \frac{7}{30} = \frac{7}{15} \times \frac{30}{7} = \frac{7 \times 30}{15 \times 7} = \frac{30}{15} = 2 \)
4. \( 6 : \frac{6}{7} = \frac{6}{1} : \frac{6}{7} = \frac{6}{1} \times \frac{7}{6} = \frac{6 \times 7}{1 \times 6} = 7 \)
5. \( 6 : 8 = \frac{6}{8} = \frac{3}{4} \)
6. \( \frac{16}{21} : 8 = \frac{16}{21} : \frac{8}{1} = \frac{16}{21} \times \frac{1}{8} = \frac{16 \times 1}{21 \times 8} = \frac{16}{168} = \frac{2}{21} \)
7. \( \frac{5}{12} : \frac{3}{10} = \frac{5}{12} \times \frac{10}{3} = \frac{5 \times 10}{12 \times 3} = \frac{50}{36} = \frac{25}{18} = 1 \frac{7}{18} \)
8. \( 1 \frac{1}{4} : 2 \frac{1}{2} = \frac{5}{4} : \frac{5}{2} = \frac{5}{4} \times \frac{2}{5} = \frac{5 \times 2}{4 \times 5} = \frac{10}{20} = \frac{1}{2} \)

Ответ: 1) \( 1 \frac{1}{5} \); 2) \( 6 \); 3) \( 2 \); 4) \( 7 \); 5) \( \frac{3}{4} \); 6) \( \frac{2}{21} \); 7) \( 1 \frac{7}{18} \); 8) \( \frac{1}{2} \).