El reino del revés is this hilarious kingdom where everything is backward and silly. The kids cracked up when we first read the lyrics (and several times after that), especially when we got to the baby with the beard. But no matter how funny it is when the dog "falls up" instead of down and spider rides on a chess piece, when they say that 2+2=3, everyone simultaneously shouts, NO!!!
We can joke about babies with beards and dogs falling up and invisible chimps, but in my class, man, math is serious business. Incorrect facts are no joke. (So they tell me.)