Respuesta:
a)
\frac{3}{4} \times \frac{4}{6} = \frac{(3 \times 4)}{(4 \times 6)} = \frac{12}{24} = \frac{1}{2}
b)
\frac{6}{8} \times \frac{2}{5} = \frac{(6 \times 2)}{(8 \times 5)} = \frac{12}{40} = \frac{3}{10}
c)
\frac{3}{7} \div \frac{1}{2} = \frac{3}{7} \times \frac{2}{1} = \frac{6}{7}
d)
\frac{6}{8} \div \frac{1}{3} = \frac{6}{8} \times \frac{3}{1} = \frac{18}{8} = \frac{9}{4}
e)
\frac{9}{12} \div \frac{2}{5} = \frac{9}{12} \times \frac{5}{2} = \frac{45}{24} = \frac{15}{8}
f)
\frac{4}{16} \div \frac{2}{3} = \frac{4}{16} \times \frac{3}{2} = \frac{12}{32} = \frac{3}{8}