Farthing:
A farthing was the smallest unit of predecimal currency in the last 100 years. A farthing was one quarter (¼) of a Penny. The last Farthing was minted in 1956.
Half Penny: (or an ‘Aipny as I recall)
As the name suggests a ‘Half Penny’ was worth one Half (½) of a Penny. So two farthings also make up half a penny. The last half penny for circulation was dated 1967.
Penny (or 1D): (plural: Pence)
The penny was really the basic unit of currency and had a lot more value than a modern ‘New’ Penny. There were 240 Pennies in a pre-decimal pound (£). The last penny for circulation was dated 1967.
Threepence (or Thrupence):
The Threepence, or ‘thrupence’ as it is also referred to was equal to three pennies. There were therefore eighty threepences in a pre-decimal pound (£). The last threepence for circulation was dated 1967.
Sixpence (or Tanner):
Also called a ‘Tanner’. Obviously worth Six Pennies. There were forty sixpences in a pre-decimal pound (£). The last sixpence for circulation was dated 1967.
Shilling (or a Bob):
A shilling was worth twelve pennies. There were 20 in the pre-decimal pound (£). The shilling was replaced by the five new pence (½0 of a decimal pound (£)). The last shilling for circulation was dated 1967 although they were used as Five pence pieces until the Five new pence (5p) coin was made smaller in 1990.
Florin (or Two Shillings, 2/-):
The Florin was worth 24 pre-decimal pence or two shillings. It was introduced by the Victorians in a step towards decimalisation, because it was worth one tenth of a pre-decimal pound (£). The last florin for circulation was dated 1967 although they were used as Ten new pence (10p) until the ten pence coin was made smaller in 1992.
Half Crown:
All the previous denominations have been worth double the denomination before them. That stops with the florin because the Half Crown was worth 30 pre-decimal pence (or two shillings and six pence). There were eight Half Crowns in a pound (£) The last half crown for circulation was dated 1967.
Crown:
A Crown was worth 60 pre-decimal pence or one quarter of a pound (£). Although in the last 30 years+ of the pre-decimal currency Crowns were really only issued to mark special occasions. Crowns are still minted today and have been given a £5 face value.
Half Sovereign and Sovereign:
Sovereigns have a face value of 20 Shillings (or one pound) and Half Sovereigns of 10 Shillings. As they are made of 22ct Gold they have a much higher real value and were not used as currency in recent years.