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
Halfpenny (Irish decimal coin) Halfpenny (Irish decimal coin) The decimal halfpenny (p) () coin was the smallest denomination of the Irish pound. It was first issued when the Irish currency was decimalised on Decimal Day, 15 February 1971. It was one of three new designs introduced all in bronze and featuring ornamental birds on the reverse. The coin value was weakened by inflation and very few were produced beyond the initial run for 1971. It was removed from circulation and demonetised on 1 January 1987. The main reason that halfpennies were issued was that when shillings were decimalised they were worth five new pence,