Decimal Day remain valid back to 1971, the only circulating coins valid on Decimal Day still to be valid. In 1982, the word "new" in "new penny" or "new pence" was removed from the inscriptions on coins, to be replaced by the number of pence in the denomination (i.e. "ten pence" or "fifty pence"). This coincided with the introduction of a new 20p coin, which, from the outset, simply bore the legend "twenty pence". A £1 coin was introduced in 1983, and a £2 coin in 1997. When the old pounds, shillings, and pence system was in operation, the United Kingdom and
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