Decimal Day use pennies or threepenny pieces, to pay them in multiples of 6d (p, the lowest common multiple of the two systems). Bus companies (at that time many state-owned by the National Bus Company) were another exception, going decimal on Sunday 21 February. Decimal Day itself went smoothly. Criticisms included the small size of the new halfpenny coin and the fact that some traders had taken advantage of the transition to raise prices. Some used new pennies as sixpences in vending machines. After 15 February, shops continued to accept payment in old coins, but always issued change in new coins. The
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