The commonest mistake a young shopkeeper makes is to look at a full cash box and feel rich. Sales are not profit. What you spent has to come out first — and until it does, you genuinely do not know how the day went.
Cost price is what you spent. Selling price is what came in. Profit is what is left when the first is taken out of the second — and if it is negative, it is a loss.
Children can recite this. What they cannot usually do is apply it when the two numbers arrive at different times of day, which is exactly what happens in real trade.
Sell 60 glasses and the cash box looks wonderful. But if you bought stock for 100 glasses and 40 melted, spoiled or went unsold, the day may still have lost money.
This is the moment the concept lands: profit is not about how much you sold, it is about the gap between what came in and what went out.
On the next day the same shopkeeper sold 41 glasses — more than before — but bought ₹300 of stock in the heat and half the ice melted. Revenue ₹492, spend ₹320, profit ₹172. More sales, less profit. That is the lesson.
In Lemonade Empire your child runs a lemonade cart and uses this exact concept to decide what to buy and what to charge. Free, no signup, plays in a browser.
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