Charlie watched 1 3 of a movie in the morning, and he watched some more at night. By the end of the day, he still had 2 5 of the movie left to watch. How much of the movie did Charlie watch at night?

4/15 of the movie

Step-by-step explanation:

In the morning, Charlie watched ¹/₃ of a movie. He then watched some more at night.

At the end of the day, he still had ²/₅ of the movie to watch.

The proportions of an item must always add up to one. This means that if you added the 1/3 to the 2/5 and then to the fraction Charlie watch at night, they should add up to one.

¹/₃ + ²/₅ + x = 1

x = 1 - ¹/₃ - ²/₅