"School Collection 20" joke

Teacher: Where is the English Channel?
Pupil: I don’t know, my TV doesn’t pick it up

Teacher: This is the third time I’ve had to tell you off this week, what have you got to say about that?
Pupil: Thank heavens it’s Friday!

Teacher: Didn’t you hear me call you?
Pupil: But you said not to answer you back!

What tables don’t you have to learn?
Dinner tables!

Why was the headmaster worried?
Because there were too many rulers in school!