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
Decimal decimal fractions were non-positional. However, counting rod fractions were positional. Qin Jiushao in his book Mathematical Treatise in Nine Sections (1247) denoted 0.96644 by J. Lennart Berggren notes that positional decimal fractions appear for the first time in a book by the Arab mathematician Abu'l-Hasan al-Uqlidisi written in the 10th century. The Jewish mathematician Immanuel Bonfils used decimal fractions around 1350, anticipating Simon Stevin, but did not develop any notation to represent them. The Persian mathematician Jamshīd al-Kāshī claimed to have discovered decimal fractions himself in the 15th century. Al Khwarizmi introduced fraction to Islamic countries in the early 9th