I think he must be plotting something.
Joke Explained
This joke is funny because it uses a clever play on words and a pun to create humor. The humor lies in the double meaning of the phrase “plotting something.”
On one hand, “plotting something” can be taken literally, suggesting that the math teacher is using the graph paper to create a plot or graph for a mathematical problem or data analysis.
On the other hand, “plotting something” can be interpreted figuratively, implying that the math teacher is planning or scheming something mischievous or secretive, similar to how someone might “plot” in a cunning manner.
The unexpected twist in the punchline, where the innocent statement about using graph paper takes on a humorous hidden meaning, is what makes this joke witty and enjoyable. It’s a great example of wordplay and how a simple pun can lead to laughter.