Joke 1:
Teacher: I think you are chewing gum.
John: No Sir, I am John Smith.

Joke 2:
Teacher: Get up. How can you sleep in my class?
Student: I can teacher, if you keep your voice down.

Joke 3:
Teacher: I told you to stand at the end of the line?
Pupil: I tried, but there was someone already there!

Joke 4:
Student: Sir, Would you mind e-mailing my exam result to my parents?
Teacher: But your parents don't have a computer.
Student: Exactly!

Joke 5:
Math teacher: Tell me Jenny, if a milkman mixes 2 liters water and 1 liter milk, he will get 3 liters. What will happen if he mixes 6 liters of water and 3 liters milk?
Student: I am not a milkman, how can I solve it?