At the time of my mother's early childhood recollections, the coins of Queen Victoria's reign (1837-1901) were still in circulation, alongside the current Edwardian ones. In May 1910 when my mother was five years old, King Edward VII died, and the early coins of King George V were added into the circulation.
2 farthings = 1 halfpenny
4 farthings = 1 penny
2 halfpennies = 1 penny
£1 = 240 pennies, or 480 halfpennies or 960 farthings
This system was known as the 'pounds, shillings and pence' system, written as £-s-d and pronounced LSD.
In the early 1900s, most of the coins in everyday use were what my mother referred to as 'coppers', i.e. pennies, halfpennies and farthings. Farthings were worth a quarter of a penny.
I started collecting coins from general circulation during the few years before decimalisation. During that time, it was not unusual to see the heads of up to five different monarchs in our change.
There were not many Victorian coins around, but it was possible to collect some if one set one's mind to it. However, at that time, Victorian coins were over 70 years old and accordingly well-worn and a muddy brown colour, rather than the salmon pink of untarnished copper fresh from the mint. Nevertheless photographs of the old coins, even in a poor state state, do give a reasonable idea of what it was like to use them.
Coppers were large and heavy compared with post-1971 decimal coins, and during the years just before decimalisation when inflation required rather a lot of coins to be carried around in order to buy anything, a general complaint was about weight. Trouser pockets quickly developed holes and purses bulged.
The weight of the coins didn't matter much in the early 1900s because a few coppers could buy so much. My mother spoke of going shopping for her grandmother with a halfpenny to buy butter. A halfpenny was a very small amount of money by the standards of later in the century. In 1971 when the United Kingdom went decimal, it would have taken 24 such halfpennies to buy just 5p of post-decimal money. My mother's pocket money as a child was one of these halfpennies a week.
For more on the buying power of the old money, put inflation into the above search box.
Silver coins were the threepenny bit (also known as the threepenny piece); the sixpence; the shilling; the two shillings (also known as the florin) and the halfcrown. There is a page on how to pronounce this old money.
a threepenny bit was worth 3 pence as its name
a sixpence was worth 6 pence as its name implies
a shilling was worth 12 pence; there were 20 shillings to the pound
a florin was worth 2 shillings; there were 10 florins to the pound
a half crown was worth 2 shillings and six pence; there were 8 half crowns to the pound
In my mother's time, silver coins really were silver. It was considered safe to put silver threepenny bits into Christmas puddings as a treat - and this may have been true as far as the metal was concerned, but many a person jarred their teeth on them.
You can see that calculations with pre-decimal money was not straightforward because the financial system was not based on tens. There were mechanical calculators, certainly in the 1950s and possibly before, although I never saw any of them.