The story in three lines. A storm takes Gullwick's bridge, and Poppa Pike needs eight planks but has three. Lan promises five before she counts, then nearly takes Vera's last plank until Rafi stops her. Two fair swaps, two lucky planks from the seven patch and one gift from the Commons make eight, and everybody lays one.

One question to ask. "Who could the island not have done without?" There is no single right answer, and that is the point: every helper did one thing the others could not. If your child says "everybody", ask them to show you why.

One thing to do at the table. You need two dice, eight paper strips for planks, and three spares of something (spoons, buttons). Lay three planks. Take turns rolling both dice; on a seven, lay a plank. Keep a tally of every total you roll. After twenty rolls, look at the tally together: which total came up most? Then swap your spares, but only spares. Ask "does it help both of us?" before each swap.

The grown-up layer. The book carries three ideas you can name if your child is curious. A fair exchange is one where both sides gain (economists call this gains from trade). With two dice, seven is the most likely total because six of the thirty-six combinations make it. And shared resources work when people take only what they need and give back what they can spare, which is the lifetime question of the economist Elinor Ostrom. You don't need to teach any of these. Asking "is that a spare or a last?" at your own table does the work.

Let your child tell the story back in their own words first. Telling it back is how a story becomes theirs.