[tex]2 \frac{1}{7} \times 1 \frac{1}{5} - \frac{1}{21} \div \frac{1}{3 } \\ \frac{14 + 1}{7} \times \frac{5 + 1}{5} - \frac{1}{21} \times \frac{3}{1} \\ \frac{15}{7} \times \frac{6}{5} - \frac{3}{21} \\ \frac{90}{35} - \frac{3}{21 } \\ \frac{18}{7} - \frac{1}{7} \\ \frac{17}{7} [/tex]
