No sooner have you arrived in Iran than you will come up against the idiosyncratic local practice of talking about prices in tomans, even though the currency is denominated in rials. One toman is worth 10 rials.

To make matters worse, taxi drivers and shopkeepers will often say ‘one’ as shorthand for IR10,000. However, before you consider cancelling your trip on the grounds of commercial confusion, rest assured that after a few days you’ll understand that the five fingers the taxi driver just showed you means IR50,000. And as you start to get a feel for what things cost, you’ll understand that if something sounds too good to be true – or too bad – it probably is.

In the interim, you can always have the price written down, and then to double-check ask whether it’s in rials or tomans – using a calculator is handy, too, as the numbers show in Western rather than Arabic numerals.

And just when you’ve mastered the rial, remember that there are plans to replace it with the toman as Iran’s official currency over the coming years.