№3 a) \( \frac{3}{8} \div \frac{9}{16} \); 6) \( 48 \div \frac{12}{13} \); в) \( \frac{11}{28} \cdot \frac{7}{33} \); г) \( 2 \frac{2}{3} \cdot 6 \); д) \( 7 \frac{11}{12} \div 3 \frac{1}{6} \).

Решение:

1. a) \( \frac{3}{8} \div \frac{9}{16} = \frac{3}{8} \cdot \frac{16}{9} = \frac{3 \cdot 16}{8 \cdot 9} = \frac{1 \cdot 2}{1 \cdot 3} = \frac{2}{3} \)
2. 6) \( 48 \div \frac{12}{13} = 48 \cdot \frac{13}{12} = \frac{48 \cdot 13}{12} = 4 \cdot 13 = 52 \)
3. в) \( \frac{11}{28} \cdot \frac{7}{33} = \frac{11 \cdot 7}{28 \cdot 33} = \frac{1 \cdot 1}{4 \cdot 3} = \frac{1}{12} \)
4. г) \( 2 \frac{2}{3} \cdot 6 = \frac{8}{3} \cdot 6 = \frac{8 \cdot 6}{3} = 8 \cdot 2 = 16 \)
5. д) \( 7 \frac{11}{12} \div 3 \frac{1}{6} = \frac{95}{12} \div \frac{19}{6} = \frac{95}{12} \cdot \frac{6}{19} = \frac{95 \cdot 6}{12 \cdot 19} = \frac{5 \cdot 1}{2 \cdot 1} = \frac{5}{2} = 2 \frac{1}{2} \)

Ответ: a) \( \frac{2}{3} \); б) 52; в) \( \frac{1}{12} \); г) 16; д) \( 2 \frac{1}{2} \).