"How do you know Mamma will give them a cookie?" I asked.
"She has to," Tom said confidently, "because she gave all the other kids a cookie." (1.59-60)
Poor Mamma is part of Tom's scheme, and she doesn't even know it. Tom definitely knows how to use someone else's goodwill to his own advantage.
"Crazy like a fox," I said, sitting on the edge of the bed and grinning triumphantly at my brothers. "Maybe I've only got a little brain, but I figured out how to get a disease first for a change. I sneaked into Howard Kay's house while he had the mumps and got him to expose me." (2.94)
It's hilarious that J.D. feels like he really got one over on his brothers. But then again, maybe he did—maybe this is exactly what he wanted. If it feels like victory, who are we to judge?
"How come they've only got stores owned by the Mormon church in Utah?" I asked.
"Shucks, J.D.," Tom said, "there are other stores in the larger towns and in the cities."
"How come they don't have any in the small towns?" I asked.
"Because the people who live in small towns are mostly Mormons," Tom said, "and the Mormons must give their business to a store owned by their church." (3.98-101)
This is a pretty resourceful solution to funding a church: If there's not enough in the offering plate, open a store that a good portion of the town will feel obligated to support.