Final answer:
Mario walked a total distance of 5.
Step-by-step explanation:
To find the total distance Mario walked, add up the distances he walked from his school to the mall, from the mall to the library, and from the library to his house.
Starting with the distance from the school to the mall, which is 2/3 mile, add it to the distance from the mall to the library, which is 1 1/3 miles, and finally add the distance from the library to his house, which is 1 3/5 miles.
Therefore, Mario walked a total distance of 5.