Imagine our class is opening a shop for one day. You have €50 to start with, six things to sell, and a whole class of hungry customers waiting at the door. Here is the big question: what would you put on the shelves, and what would you charge for each thing?

We will build one class shop together on screen, adding each item we want to sell as its own line. The bar at the top tracks how much of our €50 float we have spent on stock — that is what the stock COST us, not what we will charge. Then we work out two more numbers beside the bar: the takings and the profit. Watch which of those two really tells us whether the shop did well.

Now we design one class shop together. You call out the six things you want to sell, and we put each one in as its own line. Watch the bar fill up: it shows how much of our €50 starting float we have spent buying the stock. If one line tips us over €50, we rebalance.

Today we work through several class shops, one at a time. For each one, check the stock allocation across the items stays under the ceiling shown with none left empty, leaving room for a profit. Then work out the takings and the profit on the board.

What we did today

• Priced six items so the stock fit inside a starting float.
• Predicted the takings from a whole class of customers.
• Worked out profit as takings minus the cost of the stock.
• Tested whether a promotion can make more total profit.