Bain publishes a practice case on its own careers site about a friend who wants to open a coffee shop in Cambridge, England. The math lands on a break-even point of 204,675 cups. Then the page does something worth copying. It shows "a good answer" and then "a better answer", and the better one starts from the same arithmetic. What it adds is judgment about how long the friend needs to recoup what she spent opening the shop.

That gap is what consulting case practice exists to close. Getting the number right is table stakes. Bain's better answer keeps asking what the number means for the person who asked, and that habit forms through practice that is graded against a better answer, out loud, more than once.

Where can you find real consulting cases to practice?

Start with the firms themselves, because their cases show you what they reward. Bain's case interview preparation hub calls itself a "one-stop resource for case interview preparation" and hosts two Bain-written practice cases, Coffee Shop Co.…