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
Cocker's Decimal Arithmetick Cocker's Decimal Arithmetick Cocker's Decimal Arithmetick is a grammar school mathematics textbook written by Edward Cocker (1631–1676) and published posthumously by John Hawkins in 1684. "Decimal Arithmetick" along with companion volume, "Cocker's Arithmetick" published in 1677, were used in schools in the United Kingdom for more than 150 years. The concept of decimal fractions and the advantages of using them in calculations were well known, but a wide variety of different notations were in use. After surveying various notations, "Decimal Arithmetick" recommends the decimal point notation introduced by John Napier: "Decimal Arithmetick" gives instructions for calculations involving decimals, methods of