> 1) they are terrible at arithmetic, 2) they are terrible at algebra The interaction can be amusing. Proving algebra non-theorems by cranking through examples

> 1) they are terrible at arithmetic, 2) they are terrible at algebra The interaction can be amusing. Proving algebra non-theorems by cranking through examples until an arithmetic mistake finally leads to a "counter-example." It's like https://xkcd.com/882/ https://xkcd.com/882/ for theorems.