A pun about “missing” school is:
TEACHER: You missed school yesterday, didn’t you?
PUPIL: Not very much!
The joke—with “Not a bit!” as the punchline—was printed in many newspapers in July 1961.
10 July 1961, Austin (TX) Statesman, “Fun Time—The Riddle Box,” pg. 18, col. 5:
Teacher: Billy, you missed school yesterday, didn’t you?
Billy: Not a bit!
Google Books
Over 1500 Fantastic Jokes
By Guy Campbell; and Mark Devins
London: Dean
2002
Pg. 117:
Teacher: You missed school yesterday didn’t you?
Pupil: Not very much, no!
Google Books
August 2003, Boys’ Life, “Think & Grin,” pg. 53, col. 1:
Teacher: You missed school yesterday, didn’t you?
Johnny: Not very much. — Carlos Armenia, Signal Hill, Calif.
Google News Archive
5 July 2006, Issaquah (WA) Press, Kid County Courier, pg. 4, col. 4:
Teacher: You missed school yesterday, didn’t you?
Student. Not very much!
Google Books
The Classroom Zone:
Jokes, Riddles, Tongue Twisters & “Daffynitions”
By Gary Chmielewski
Chicago, IL: Norwood House Press
2008
Pg. 21:
Principal Howland: “Michael, you missed school yesterday, didn’t you?”
Michael: “Not very much!”
Google Books
Super Hot Jokes For Cool Kids!
By Various Authors
London: Buster Books
2014
Pg. ?:
Teacher: You missed school yesterday, didn’t you?
Pupil: Not very much.
Twitter
Funny Jokes
@iJokeTime
Teacher: Tim, you missed school yesterday, didn’t you?
Tim: Not a bit!
5:59 AM - 4 Dec 2015