The Witches Youth Quotes

How we cite our quotes: (Chapter.Paragraph)

Quote #10

Only the children in the room were really enjoying it. They all seemed to know instinctively that something good was going on right there in front of them, and they were clapping and cheering and laughing like mad. (20.16)

Where did all these children come from? Why did Roald Dahl decide to insert this thought at the very end of the book when there had barely been any children throughout the rest of the story?