Diego will ship 8 boxes in a large carton that is the shape of a right rectangular prism. Each box is 13 inches by 5 inches by 6 inches. Diego determined the volume of one box by calculating (13 + 5 + 13 + 5) x 6.

Determine whether Diego is correct or incorrect.
If Diego is correct,
show or explain how you know he is correct
Include the volume in your work or explanation
If Diego is incorrect,
Find the correct answer
Show or explain the steps you used to find the correct answer. Include the correct answer in your work or explanation.

Enter your work and explanation in the space provided.