Before 1971 the British money system was far from decimal. I had a number of jobs that involved money, either hard cash or on paper, and it inevitably involved some arithmetic. This was before the invention of the electronic calculator, and everybody had to do their calculating by hand, or more correctly, in our heads.
The basic units of English money were L, S, and D. The L stood for the Latin word Libra, or pound. The S stood for the Germanic word shilling, and the D stood for the Germanic word penny. But why the D? The D stood for denarius, which was a Roman coin.
At one time in the distant past, the penny had real value. In 1672, it was divided into two half pennies—pronounced hay’pny--and then in 1714, it was divided again, this time into quarters called farthings, from an Anglo-Saxon word.
The shilling (often called a bob) was worth twelve pennies. It was divided into a six-penny coin (often called a tanner) and a three-penny coin (usually called a thrippny bit). There was also a two-shilling coin called a florin (or a two-bob bit) that was introduced in 1849. Its name was based on a Florentine coin.
The half crown coin, which was larger than the florin, had been around since the 16th century. Its value was two shillings and six pence. Although it was called a half crown, the crown coin didn’t really exist anymore. The first crowns were large silver coins based on the famous Spanish Pieces of Eight, but they were just too heavy to carry around. Today the crown is a ceremonial coin produced only on special occasions.
The pound coin only appeared with decimalization in 1971. Before that, pounds were paper money. For centuries, the highest value coin was the gold guinea, which was officially worth twenty shillings, although in practice it was always valued at twenty-one shillings. Guineas did not circulate and I never actually saw one. Today the word is often used in racing and auctions. The name came from the African country of Guinea, where the gold originally came from.
Now that you are thoroughly confused, imagine the plight of the little schoolboy who has to multiply seven pounds eight shillings and nine pennies (7/8/9) or (L7-S8-D9) by 13, or the store clerk who has to make change for one pound seventeen shillings eight and a half pennies from a five-pound note. We did it. We did it quickly. And without the help of calculators.