Decimal Day weights and measures.) Around the time of Decimalisation Day, "Decimal Adders" and other converters were available to help people convert between the old and new coins. The following is a table showing conversions between the decimal and pre-decimal systems. All pre-decimal coins (except for certain non-circulating coins such as crowns, sovereigns, and double florins which were explicitly excluded from demonetisation) are now no longer legal tender. Public outcry at the proposed demise of the old sixpence (6d), worth exactly p and originally slated for early withdrawal, postponed its withdrawal until June 1980. Shillings and florins, together with their same-sized 5p
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