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
Penny (Irish pre-decimal coin) Penny (Irish pre-decimal coin) The penny (1d) () coin was the third smallest denomination of the pre-decimal Irish pound, worth of a pound or of a shilling. To express an amount, penny was abbreviated to "d", e.g. 1d, from the Roman "denarius". It was introduced in 1928 to replace its British counterpart, used when all of Ireland was a constituent country of the United Kingdom. The last year of minting was 1968 and it ceased to be legal tender on 31 December 1971. The coin measured in diameter and weighed 9.45 grams. The bronze coin was made up of 95.5%