Why was the math book depressed?

This joke plays on a classic comedic device: wordplay, specifically a pun. The humor stems from the double meaning of the word "problems." In the context of a math book, "problems" refers to the exercises and equations students are meant to solve. However, when applied to a living being, "problems" signifies difficulties, worries, or issues that can lead to feelings of sadness or depression.

The cleverness here lies in taking a common, inanimate object like a math book, which is inherently full of numerical challenges, and anthropomorphizing it by giving it human emotions and struggles. We've all faced academic "problems" ourselves, and the idea of a book feeling overwhelmed by its own content creates a relatable, albeit absurd, image. It's a lighthearted jab at the sometimes daunting nature of mathematics and the universal experience of feeling burdened by too many things to deal with.