This expression is a limerick. Translate it into English, and it will scan perfectly. There are several possibilities for the last line, but be very fussy about the rhythm.
Solution
“A dozen, a gross, and a score,
Plus three times the square root of four,
Divided by seven,
Plus five times eleven,
Comes out to nine squared and no more.”
(Or, “is 9 squared and not a bit more.”)
This is a fun problem to do as a class activity. You'll need to prime the pump with "OK what's another word for 12?" That's not so hard; coming up with a gross is harder. Score comes from the Gettysburg address. has a nice rhythm if you say it right. And off you go.