Calculați fractia "))

[tex]( - \frac{9}{8} ) \times ( - \frac{4}{15} ) \times ( + \frac{10}{21} ) = [/tex]
[tex] \frac{9 \times 4}{8 \times 15} \times \frac{10}{21} = [/tex]
[tex] \frac{3}{2 \times 5} \times \frac{10}{21} = [/tex]
[tex] = \frac{1}{1} \times \frac{1}{7} [/tex]
[tex] = \frac{1}{7} [/tex]