In Britain I think of the pound as “twice a dollar” (which it is, almost exactly) and I think of the Euro as “a dollar and a half.” But a Danish kroner is worth 21 cents Canadian, which makes for more on-the-flay mathematics than my mind can handle. So I settle on everyday mnemonics. Here’s the ones I came up with:

• Cost of a flat: 1,000,000 DKK.
• Monthly mortgage payment on a flat: 10,000 DKK.
• Cost to have a cat’s ball joint repaired: 5,000 DKK.
• Return ticket to Sweden on the train: 175 DKK.
• Cost for a few days worth of groceries: 100 DKK.
• Film ticket (afternoon): 60 DKK.
• A large cappuccino: 30 DKK.
• A good machiatto: 22 DKK.
• A croissant: 12 DKK.

Since I learned it from Peter Livingstone, my main unit of mnemonic currency for large items is the cat ball joint repair: I see a new car advertised in a magazine and I think “oh, that’s 100 cat ball joints worth,” or a two-week flat rental (1 ball joint job).