Find the surface area (area of all faces) of a cube whose edge length is 5 dm, 4 m.

Let us determine the surface area of the specified cube, knowing that it is, by definition, equal to the sum of the areas of its six faces (that is, six identical squares) and that in this particular case, the length of its edge is 5 decimeters:

5 * 5 * 6 = 150.

Let us determine the surface area of the indicated cube, knowing by the condition of the problem that the length of its edge is 4 meters:

4 * 4 * 6 = 96.

Answer: The surface area of the cube in the first case is 150 dm2. The surface area of the cube in the second case is 96 m2.