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 separator In the Middle Ages, before printing, a bar ( ¯ ) over the units digit was used to separate the integral part of a number from its fractional part, e.g. 995 (meaning, 99.95 in decimal point format). This practice derived from the decimal system used in Indian mathematics and was popularized by the Persian mathematician Al-Khwarizmi, when Latin translation of his work on the Indian numerals introduced the decimal positional number system to the Western world. His "Compendious Book on Calculation by Completion and Balancing" presented the first systematic solution of linear and quadratic equations in Arabic. A similar notation