1. (10 points) Calculate: $\left(\frac{1}{\frac{7}{9}}-\frac{\frac{3}{5}}{7}\right) \times \frac{11}{6 \frac{3}{5}} \div \frac{4}{13}-2.4=$
【Analysis】Start by calculating from the parentheses, simplify first, then cleverly calculate the original expression, and finally obtain the result of the original expression.
【Solution】According to the analysis, the original expression $=\left(\frac{1}{\frac{7}{9}}-\frac{\frac{3}{5}}{7}\right) \times \frac{11}{6 \frac{3}{5}} \div \frac{4}{13}-2.4$
$$
\begin{array}{l}
=\left(\frac{9}{7}-\frac{3}{35}\right) \times \frac{11}{\frac{33}{5}} \div \frac{4}{13}-2.4 \\
=\left(\frac{9}{7}-\frac{3}{35}\right) \times 11 \times \frac{5}{33} \times \frac{13}{4}-2.4 \\
=\left(\frac{9}{7}-\frac{3}{35}\right) \times \frac{5 \times 13}{12}-2.4 \\
=\frac{9}{7} \times \frac{5 \times 13}{12}-\frac{3}{35} \times \frac{5 \times 13}{12}-2.4 \\
=\frac{3 \times 5 \times 13}{7 \times 4}-\frac{13}{7 \times 4}-2.4 \\
=\frac{13}{7 \times 4}(3 \times 5-1)-2.4 \\
=\frac{13 \times 14}{7 \times 4}-2.4 \\
=\frac{13 \times 7 \times 2}{7 \times 4}-2.4 \\
=\frac{13}{2}-2.4 \\
=6.5-2.4 \\
=4.1
\end{array}
$$

Therefore, the answer is: 4.1.