lpetrich
Contributor
On Decimal Day, 15 February 1971, Britain introduced a new division of its unit of currency, the pound sterling. In it, the penny changed from 1/240 pound to 1/100 pound, and intermediate values were changed to decimal-style multiples of pence: 2, 5, 10, 20, and 50, much as Britain's rebellious North American colonies had done nearly two centuries before.
Pre-decimal money quantities were usually given as pounds - shillings - pence.
The decimal-currency penny was 2.4 times the old penny, and a new-penny half-penny coin was issued for a while to help ease the transition.
Coins of the pound sterling, List of British banknotes and coins
Pre-decimal coins – What do you know about farthings, florins and groats?
Pre-decimal currency in Britain (before 1971)
From this table, one can easily discern a preference for multiples and reciprocal multiples, and also for powers of 2. I counted these prime factors in all its numbers: {{1, 112}, {2, 316}, {3, 92}, {5, 56}, {7, 24}}. The 1's are from numerators or denominators being 1. Doing this on every possible pairing of coin gives {{1, 744}, {2, 2414}, {3, 778}, {5, 490}, {7, 288}}. The 7's come from the guineas, and omitting them gives {{1, 96}, {2, 266}, {3, 60}, {5, 48}} for this table, and {{1, 546}, {2, 1702}, {3, 404}, {5, 344}} for all possible coin combinations.
Pre-decimal money quantities were usually given as pounds - shillings - pence.
The decimal-currency penny was 2.4 times the old penny, and a new-penny half-penny coin was issued for a while to help ease the transition.
Coins of the pound sterling, List of British banknotes and coins
Pre-decimal coins – What do you know about farthings, florins and groats?
Pre-decimal currency in Britain (before 1971)
From this table, one can easily discern a preference for multiples and reciprocal multiples, and also for powers of 2. I counted these prime factors in all its numbers: {{1, 112}, {2, 316}, {3, 92}, {5, 56}, {7, 24}}. The 1's are from numerators or denominators being 1. Doing this on every possible pairing of coin gives {{1, 744}, {2, 2414}, {3, 778}, {5, 490}, {7, 288}}. The 7's come from the guineas, and omitting them gives {{1, 96}, {2, 266}, {3, 60}, {5, 48}} for this table, and {{1, 546}, {2, 1702}, {3, 404}, {5, 344}} for all possible coin combinations.
Coin | Farthing | Penny | Shilling | Pound |
Mite | 1/6 | 1/24 | 1/288 | 1/5760 |
Quarter farthing | 1/4 | 1/16 | 1/192 | 1/3840 |
Third farthing | 1/3 | 1/12 | 1/144 | 1/2880 |
Half farthing | 1/2 | 1/8 | 1/96 | 1/1920 |
Farthing | 1 | 1/4 | 1/48 | 1/960 |
Halfpenny | 2 | 1/2 | 1/24 | 1/480 |
Three farthings | 3 | 3/4 | 1/16 | 1/320 |
Penny | 4 | 1 | 1/12 | 1/240 |
Three halfpence | 6 | 1 1/2 | 1/8 | 1/160 |
Twopence, half-groat | 8 | 2 | 1/6 | 1/120 |
Threepence | 12 | 3 | 1/4 | 1/80 |
Groat | 16 | 4 | 1/3 | 1/60 |
Sixpence | 24 | 6 | 1/2 | 1/40 |
Shilling | 48 | 12 | 1 | 1/20 |
Florin | 96 | 24 | 2 | 1/10 |
Half-crown | 120 | 30 | 2 1/2 | 1/8 |
Double florin | 192 | 48 | 4 | 1/5 |
Crown | 240 | 60 | 5 | 1/4 |
Quarter guinea | 252 | 63 | 5 1/4 | 21/80 |
Third guinea | 336 | 84 | 7 | 7/20 |
Halfpound, half sovereign | 480 | 120 | 10 | 1/2 |
Half guinea | 504 | 126 | 10 1/2 | 21/40 |
Pound, sovereign, unite, laurel | 960 | 240 | 20 | 1 |
Guinea | 1008 | 252 | 21 | 21/20 |
Two pounds | 1920 | 480 | 40 | 2 |
Two guineas | 2016 | 504 | 42 | 21/10 |
Fifty shillings | 2400 | 600 | 50 | 5/2 |
Triple unite | 2880 | 720 | 60 | 3 |
Five pounds | 4800 | 1200 | 100 | 5 |
Five guineas | 5040 | 1260 | 105 | 21/4 |