7. (3 points) A rectangular wooden block with a length of 25 cm, a width of 10 cm, and a height of 4 cm is sawed into several equal-sized cubes, which are then assembled into a large cube. The surface area of this large cube is $\qquad$ square centimeters.
【Solution】Solution: The number of 1 cm edge cubes that can be sawed from a rectangular wooden block with a length of 25 cm, a width of 10 cm, and a height of 4 cm: $25 \times 10 \times 4=1000$;
The length, width, and height of a large cube formed by 1000 small cubes are 10 cm, because $10 \times 10 \times 10=1000$; therefore, the surface area of this large cube is: $10 \times 10 \times 6=600$ square cm; Answer: The surface area of this large cube is 600 square cm. Therefore, the answer is: 600 .