I’m recounting to my father an episode that happened in a shop.
My father will always see scheming behind everyone’s smallest actions, and this, in particular, from anyone setting rules. He also hates this particular chain of shops for political reasons, so all his buttons are being pushed.
Me: “…and they’re getting rid of the smallest coins. So this customer is paying at the counter, and the cashier says, ‘That’ll be 24.50’, and she goes, ‘But it’s 24.48!’ And the cashier says, ‘We have started rounding to the nearest five’, and she’s like, ‘You’re robbing me!’, and he explains…”
Father: “Of course they are!”
Me: “What?”
Father: “Of course they’re robbing her! Forty-eight rounded to fifty, they’re getting two cents from every sale, do you have any idea how much money it is at the end of the year?”
Me: “Of course I do, but that does not happen, because, as the signs around the shop were saying, and as the cashier explained, there is an equal chance that it’s rounded down. Zero and five are unchanged, 1, 2, 6, and 7 are rounded down, 3, 4, 8, and 9 are rounded up. In a year, the shop gets no money from rounding.”
Father: “That’s what they want you to think! Because all they need to do is to make the last figure always a 3 or 4 or 8 or 9…”
Me: “…and ‘they’ can also control how the items in your cart add up to a sum always ending in 3, 4, 8, or 9? However, as the cashier said, if you’re so worried that the chain takes away a cent too much, you can always pay with your card, where there is no rounding. And we finally have the proven evidence that you reason exactly like one of those customers, Dad.”