"We’ll never run out of math teachers because they always multiply” is a jocular one-line saying that has been printed on several images. The math pun has been cited in print since at least January 2007.

Google Groups: rec.crafts.textiles.needlework

OT-Puns for the Punny

*Lucille *

1/15/07

(...)

>>>> >* We’ll never run out of math teachers because they always multiply.

19 January 2007, Pensacola (FL) *News Journal*, “Just Awful Jokes,” pg. 3B, col. 3:

We’ll never run out of math teachers because they always multiply.

18 February 2007, Edmonton (Alberta) *Journal*, “Why Barney tunes get stuck in your head” by Terry McConnell, pg. E2:

We’ll never run out of math teachers because they always multiply.

Twitter

Don Myers

@azthumper

We’ll never run out of math teachers, because they always multiply! lol

1:48 PM - 8 Apr 2009

Google Books

*Teaching Language Arts to English Language Learners*

By Anete Vásquez, Angela L. Hansen and Philip C. Smith

New York, NY: Routledge

2010

Pg. ?:

We’ll never run out of math teachers because they always ______. (multiply)

Google Books

*The Laugh-a-Day Book of Bloopers, Quotes & Good Clean Jokes*

By Jim Kraus

Grand Rapids, MI: Revell

2012

Pg. ? (Day 68):

We’ll never run out of math teachers because they always multiply.

Twitter

Miss Lynch’s Class

@mramathletes

Why don’t we ever run out of math teachers? Because they multiply!!! Have a Factoring Friday Mathletes!

6:00 AM - 25 Aug 2017

Twitter

sho ⚔️

@shoreadytofight

we’ll never run out of math teachers because they always multiply ⚔️🗡⚔️

10:37 PM - 23 Jan 2018