Non-decimal currency Non-decimal currency A non-decimal currency is a currency that has sub-units that are a non-decimal fraction of the main unit, i.e. the number of sub-units in a main unit is not a power of 10. Today only two countries in the world use non-decimal currencies. Both of these countries are in Africa. These are Mauritania (1 ouguiya = 5 khoums) and Madagascar (1 ariary = 5 iraimbilanja). However these are only theoretically non-decimal, as in both cases the value of the main unit is so low that the sub-unit is too small to be of any practical use and coins
Manx pound and there is no guarantee of convertibility beyond that given by the Manx authorities. However, the requirement in the island's Currency Act 1992 for the Isle of Man Treasury to exchange Manx Pound banknotes on demand for Bank of England notes in practice restricts the issue of unbacked currency, and the aggregate total of notes issued must be pre-approved by Tynwald. ISO 4217 does not include a separate currency code for the Manx pound, but where code distinct from GBP is desired, "IMP" is generally used. UK notes and coins (whether from banks in England, Scotland, or Northern Ireland) are