1. (8 points) The calculation result of the expression $20.15 \div(1.2+1.9) \times\left(4^{2}-3^{2}+2^{2}-1^{2}\right)$ is
【Solution】Solve: $20.15 \div(1.2+1.9) \times\left(4^{2}-3^{2}+2^{2}-1^{2}\right)$
$$
\begin{array}{l}
=20.15 \div 3.1 \times 10 \\
=6.5 \times 10 \\
=65
\end{array}
$$

Therefore, the answer is: 65.