1. (10 points) Calculate: $19 \times 75 + 23 \times 25=$
【Analysis】Decompose 75 into $3 \times 25$, then use the distributive property of multiplication to combine the 23, which results in $80 \times 25$.

【Solution】Solution: $19 \times 75+23 \times 25$
$$
\begin{array}{l}
=19 \times 3 \times 25+23 \times 25 \\
=57 \times 25+23 \times 25 \\
=25 \times(57+23) \\
=25 \times 80 \\
=2000
\end{array}
$$

Therefore, the answer is: 2000
【Comment】This problem tests the skillful calculation of four basic operations. The key to solving this problem is: decomposing 75 into $3 \times 25$, then using the distributive property of multiplication to find the answer.