Decimal Day old coins were returned to the banks and in this way the bulk of them were quickly taken out of circulation. The new halfpenny, penny, and twopence coins were introduced on 15 February 1971. Within two weeks of Decimal Day, the old penny (1d) and old threepenny (3d) coins had left circulation, and old sixpences were becoming rare. On 31 August 1971, the 1d and 3d were officially withdrawn from circulation, ending the transition period. The government intended that in speech the new units would be called "new pence", but the public decided that it was clearer and quicker to
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