I'm definitely not as smart as a 4 year old

Danny and Holden wanted to bake today. Last week we made peanut butter cookies. Only one problem we forgot the peanut butter. So we went to the store to get some ingredients. Before we walked in I explained what kind of behavior I expected and what would happen if they misbehaved. Danny hit Holden once and then they got in to a shoving match. We barely got in before I carried Holden and held Danny's hand and we got in the car and went home. Both cried the whole way home, "I wanna go to the store." Danny bad mouthed me on the way in so he went to his room. I told him to stay there for 5 minutes. HE kept telling me over and over how he wasn't going to and that he was going to watch tv. I planned ahead and locked the playroom door from the inside so he couldn't get in. I came back downstairs to make lunch. When I went back in his room I discovered he was in the locked playroom. He used a credit card to unlock the door and was sitting on his chair watching a movie he put in himself.