1. Calculate: $78 \cdot 35 \cdot 379 + 78 \cdot 35 + 78 \cdot 35 \cdot 620 - 2000 \cdot 39 \cdot 34$.
First method:

Let's solve the problem by applying distributivity, or by factoring out the common factor:

$$
\begin{array}{ll}
78 \cdot 35 \cdot 379+78 \cdot 35+78 \cdot 35 \cdot 620-2000 \cdot 39 \cdot 34= & \\
=78 \cdot 35 \cdot 379+78 \cdot 35 \cdot 1+78 \cdot 35 \cdot 620-2000 \cdot 39 \cdot 34= & \\
=78 \cdot 35 \cdot(379+1+620)-2000 \cdot 39 \cdot 34= & 1 \text{ POINT} \\
=78 \cdot 35 \cdot 1000-2000 \cdot 39 \cdot 34= & 1 \text{ POINT} \\
=35 \cdot 78000-78000 \cdot 34= & 1 \text{ POINT} \\
=78000 \cdot(35-34)= & 1 \text{ POINT} \\
=78000 & 1 \text{ POINT}
\end{array}
$$