To determine how many of the 160 cubes have at least one face painted green, let's follow these steps:

1. Calculate the volume and the number of small cubes:

   • The original rectangular prism has dimensions 4 units by 5 units by 8 units.
   • The volume of the prism is $4 \times 5 \times 8 = 160$ cubic units.
   • Since the prism is cut into 160 cubes, each cube is $1 \times 1 \times 1$ unit in dimension.

2. Identify the cubes that do not have any painted faces:

   • To find the cubes that do not have any painted faces, consider the cubes that are entirely inside the prism, not touching any of the outer faces.
   • These inner cubes form a smaller rectangular prism, excluding the outer layer of cubes. This smaller prism will have dimensions reduced by 2 units on each dimension (one unit for each side of a dimension).
   • Dimensions of the inner rectangular prism: $(4-2) \times (5-2) \times (8-2) = 2 \times 3 \times 6$.

3. Calculate the number of inner cubes:

   • The volume of this inner rectangular prism is $2 \times 3 \times 6 = 36$ cubes.

4. Subtract the number of inner cubes from the total number of cubes:

   • Total number of cubes = 160.
   • Number of inner cubes = 36.
   • Number of cubes with at least one face painted = Total cubes - Inner cubes.
   • $160 - 36 = 124$.

Therefore, the number of cubes that have at least one face painted green is $\boxed{124}$.

Would you like more details or have any questions about this solution?

Here are 5 more questions you might be interested in:

1. How many edges does a rectangular prism have?
2. What is the surface area of the original rectangular prism?
3. How do you calculate the volume of a cylinder?
4. What is the Pythagorean theorem and how is it used in geometry?
5. How do you find the area of a triangle given its base and height?

Tip: When tackling geometric problems, visualizing or sketching the shapes involved can significantly aid in understanding and solving the problem accurately.