The International Prototype Kilogram (IPK) is a thing in France that is exactly 1kg.
What if someone goes to France to buy a souvenir of the IPK but only has British Pounds?
The cashier would say "That's 1.09 Euros. Oh, you only have pounds. Then, that's one pound."
But I thought the IPK was supposed to be 1 kg, not 1 lb.
