2. (6 points) Given $16.2 \times\left[\left(4 \frac{1}{7}-\square \times 700\right) \div 1 \frac{2}{7}\right]=8.1$, then $\square=$

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2. (6 points) Given $16.2 \times\left[\left(4 \frac{1}{7}-\square \times 700\right) \div 1 \frac{2}{7}\right]=8.1$, then $\square=\underline{0.005}$.
【Solution】Solution: $16.2 \times\left[\left(4 \frac{1}{7}-\square \times 700\right) \div 1 \frac{2}{7}\right]=8.1$,
$$
\begin{array}{l}
\left(4 \frac{1}{7}-\square \times 700\right) \div 1 \frac{2}{7}=8.1 \div 16.2, \\
4 \frac{1}{7}-\square \times 700=8.1 \div 16.2 \times 1 \frac{2}{7}, \\
\square \times 700=4 \frac{1}{7}-8.1 \div 16.2 \times 1 \frac{2}{7}, \\
\square=\left(4 \frac{1}{7}-8.1 \div 16.2 \times 1 \frac{2}{7}\right) \div 700, \\
\square=\left(\frac{29}{7}-\frac{4.5}{7}\right) \div 700, \\
\square=\frac{24.5}{7} \times \frac{1}{700}, \\
\square=0.005 .
\end{array}
$$

Therefore, the answer is: 0.005.