 What is the central irony at the end of the story? He ends up becoming an employee of children
They manufacture simple compositions like polishing waxes and sell them from door-to-door. Marjorie put back her head and laughed, and I was forced to join her, for we both recognize that my understanding and "feel" for commercial matters—if I may use that expression—is almost nonexistent. This was to be our headquarters and factory for the summer—a roomy unused barn belonging to the parents of one of the group members, Tommy Miller. Mary McCready was a big husky redhead of twelve, with a face full of freckles and an infectious laugh, and Tommy Miller, a few months younger, was just an average, extroverted, well adjusted youngster, noisy and restless, tee-shirted and butch-barbered.
 While Donald is excited about the opportunity to impart his knowledge, he becomes the employee of students who have more qualifications than he does
 While Donald feels insecure regarding his science background, he becomes more confident due to his experience innovating with the children  While Donald initially expresses concern about selling items door-to-door, all the customers end up coming to him and the group members  While Donald is excited about the opportunity to impart his knowledge, he becomes the employee of students who have more qualifications than he does  While Donald despises teaching, he ends up committing to more teaching-related responsibilities over the course of a school year