The other day in class the attendance secretary came to fetch one of my students. His dad was there to pick him up for a doctor appointment. He gathered his belongings and then hesitated at the door. With a concerned expression he turned around and approached my desk. The other students were working quietly on an assignment, so he whispered his request. "Will you tell (here he named another student) to give me my money?"
It was my turn to be concerned. "Why does he have your money?" I asked.
"Because we traded," he explained.
I was confused. "What did you trade?"
"I gave him my money and he gave me those cards." He pointed to the table where a deck of cards still lay.
"We call that 'buying' when we trade money for something," I told him, and looking sternly at both boys, I continued, "and we don't use class time to conduct that kind of business."
"But I changed my mind," the first kid said with a slight whimper, "and I need my money back. My dad will be mad."
The card seller had the sense to look abashed, but he kept the cash in his pocket. I sighed and canceled the transaction. "Give him his money and get back to work."