1. (3 points) Calculate
(1) $0.45 \times 2.5 + 4.5 \times 0.65 + 0.45=$ $\qquad$ ;
(2) $1 + 3 + 5 + 7 + \cdots + 49=$ $\qquad$
1. (3 points) Calculate
(1) $0.45 \times 2.5+4.5 \times 0.65+0.45=4.5$;
(2) $1+3+5+7+\cdots+49=625$.
【Solution】Solution: (1) $0.45 \times 2.5+4.5 \times 0.65+0.45$,
$$
\begin{array}{l}
=0.45 \times 2.5+0.45 \times 6.5+0.45, \\
=0.45 \times(2.5+6.5+1), \\
=0.45 \times 10, \\
=4.5 ;
\end{array}
$$
$$
\begin{aligned}
& \text { (2) } 1+3+5+7+\cdots+49, \\
= & (1+49)+(3+47)+(5+45)+\cdots+(23+27)+25, \\
= & 50 \times 12+25, \\
= & 600+25, \\
= & 625 .
\end{aligned}
$$

Therefore, the answers are: $4.5,625$.