The story in three lines. The third span needs a box of nails that costs twelve coins, and Gullwick swaps instead of using coins. The children run a lemonade stand for the ferry passengers on supplies Gilly lends them, and Cost, Price, Coin and Profit each handle one part of the sums. When the tin holds twenty coins, Lan nearly spends all of it on a shiny box until Profit reminds her that eight of those coins are Gilly's.

One question to ask. "Was the twenty coins theirs?" Let your child work out why it wasn't, and how much really was.

One thing to do at the table. Run a pretend stand with real coins or counters. Before you "sell" anything, write down what the supplies cost on a scrap of paper. Choose a price and write it on a sign. Take turns being the customer who pays with a big coin, and count up from the price to give change. At the end, take away the cost and see what is left.

The grown-up layer. The book uses four words that children often mix up. Cost is what the supplies cost. Price is what you charge. Takings (or revenue) is what comes into the tin. Profit is takings minus costs. Counting up to make change is how many cashiers were taught before tills did it for them, and it is often easier for children than subtraction. The bigger idea is in the token word, ENOUGH: the stand was for a bridge, so the goal was the right amount, paid for fairly, not as much as possible.

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