1. If the length is 25 cm, you can cut a cube with a side length of 5 cm, and you can get that the width and height of the original cuboid are 5 cm, so you can judge that the length of the new cuboid is 25-5=20 cm and the width and height are 5 cm. The surface area of a new cuboid is s = (5× 5+20× 5+20× 5 )× 2 = 450 cm2; The volume of the original cuboid V=5×5×25=625 cubic centimeters.

2. To calculate the side length of a cube, you need to know the circumference of the cuboid. From the length, width and height of the original cube, the circumference of the original cuboid is c = (10+5+3) × 4 = 72 cm; Then the side length of the new cube is a=72÷ 12=6 cm.

3. After cutting into three cuboids, add four surfaces. From this, we can calculate that the width, height and surface area of the original cuboid is S= 100÷4=25, and then according to the length, we can get the volume of the original cuboid V=25× 15=375 cubic centimeters.

4. To cut into 9 segments, it needs to be cut 8 times, so the ratio of the number of cuts to the number of segments is 8:9, that is, the number is 8/9 of the number of segments. Similarly, cutting into 10 segments is 9/ 10, and if it needs to be cut into n segments, it is (n-1)/n.

Note: I answered these four questions on the spot and didn't copy anyone's. In addition, I don't know what 8 meters is in the fourth question, and I don't think 8 meters has anything to do with this topic.