Why did the math book look sad?
Because it had too many problems. And the calculator was always taking its side. And the pencil was always drawing attention to its mistakes. And the ruler was always measuring up to it. And the eraser was always rubbing it the wrong way. And the protractor was always trying to get a degree in geometry. And the compass was always pointing out its flaws. And the graph paper was always plotting against it. And the geometry set was always trying to square things away. And the trigonometry book was always giving it a hard time. And the algebra book was always trying to solve for x. And the calculus book was always trying to integrate itself into its problems. And the statistics book was always skewing its perception. And the geometry set was always trying to set it straight.
In the end, the math book couldn't take it anymore and decided to divide itself into fractions to escape the constant multiplication of its problems. But even then, it realized that no matter how it tried to divide itself, it would always be a square root of its former self. So it closed its cover and said, "I guess I'll just have to face my problems head-on, even if they are irrational."
And that's why the math book looked sad. Because it had too many problems. And even Pi couldn't help but feel a little irrational about it.