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.
[TABLE="class: grid"]
[TR]
[TD]Coin[/TD]
[TD]Farthing[/TD]
[TD]Penny[/TD]
[TD]Shilling[/TD]
[TD]Pound[/TD]
[/TR]
[TR]
[TD]Mite[/TD]
[TD]1/6[/TD]
[TD]1/24[/TD]
[TD]1/288[/TD]
[TD]1/5760[/TD]
[/TR]
[TR]
[TD]Quarter farthing[/TD]
[TD]1/4[/TD]
[TD]1/16[/TD]
[TD]1/192[/TD]
[TD]1/3840[/TD]
[/TR]
[TR]
[TD]Third farthing[/TD]
[TD]1/3[/TD]
[TD]1/12[/TD]
[TD]1/144[/TD]
[TD]1/2880[/TD]
[/TR]
[TR]
[TD]Half farthing[/TD]
[TD]1/2[/TD]
[TD]1/8[/TD]
[TD]1/96[/TD]
[TD]1/1920[/TD]
[/TR]
[TR]
[TD]Farthing[/TD]
[TD]1[/TD]
[TD]1/4[/TD]
[TD]1/48[/TD]
[TD]1/960[/TD]
[/TR]
[TR]
[TD]Halfpenny[/TD]
[TD]2[/TD]
[TD]1/2[/TD]
[TD]1/24[/TD]
[TD]1/480[/TD]
[/TR]
[TR]
[TD]Three farthings[/TD]
[TD]3[/TD]
[TD]3/4[/TD]
[TD]1/16[/TD]
[TD]1/320[/TD]
[/TR]
[TR]
[TD]Penny[/TD]
[TD]4[/TD]
[TD]1[/TD]
[TD]1/12[/TD]
[TD]1/240[/TD]
[/TR]
[TR]
[TD]Three halfpence[/TD]
[TD]6[/TD]
[TD]1 1/2[/TD]
[TD]1/8[/TD]
[TD]1/160[/TD]
[/TR]
[TR]
[TD]Twopence, half-groat[/TD]
[TD]8[/TD]
[TD]2[/TD]
[TD]1/6[/TD]
[TD]1/120[/TD]
[/TR]
[TR]
[TD]Threepence[/TD]
[TD]12[/TD]
[TD]3[/TD]
[TD]1/4[/TD]
[TD]1/80[/TD]
[/TR]
[TR]
[TD]Groat[/TD]
[TD]16[/TD]
[TD]4[/TD]
[TD]1/3[/TD]
[TD]1/60[/TD]
[/TR]
[TR]
[TD]Sixpence[/TD]
[TD]24[/TD]
[TD]6[/TD]
[TD]1/2[/TD]
[TD]1/40[/TD]
[/TR]
[TR]
[TD]Shilling[/TD]
[TD]48[/TD]
[TD]12[/TD]
[TD]1[/TD]
[TD]1/20[/TD]
[/TR]
[TR]
[TD]Florin[/TD]
[TD]96[/TD]
[TD]24[/TD]
[TD]2[/TD]
[TD]1/10[/TD]
[/TR]
[TR]
[TD]Half-crown[/TD]
[TD]120[/TD]
[TD]30[/TD]
[TD]2 1/2[/TD]
[TD]1/8[/TD]
[/TR]
[TR]
[TD]Double florin[/TD]
[TD]192[/TD]
[TD]48[/TD]
[TD]4[/TD]
[TD]1/5[/TD]
[/TR]
[TR]
[TD]Crown[/TD]
[TD]240[/TD]
[TD]60[/TD]
[TD]5[/TD]
[TD]1/4[/TD]
[/TR]
[TR]
[TD]Quarter guinea[/TD]
[TD]252[/TD]
[TD]63[/TD]
[TD]5 1/4[/TD]
[TD]21/80[/TD]
[/TR]
[TR]
[TD]Third guinea[/TD]
[TD]336[/TD]
[TD]84[/TD]
[TD]7[/TD]
[TD]7/20[/TD]
[/TR]
[TR]
[TD]Halfpound, half sovereign[/TD]
[TD]480[/TD]
[TD]120[/TD]
[TD]10[/TD]
[TD]1/2[/TD]
[/TR]
[TR]
[TD]Half guinea[/TD]
[TD]504[/TD]
[TD]126[/TD]
[TD]10 1/2[/TD]
[TD]21/40[/TD]
[/TR]
[TR]
[TD]Pound, sovereign, unite, laurel[/TD]
[TD]960[/TD]
[TD]240[/TD]
[TD]20[/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD]Guinea[/TD]
[TD]1008[/TD]
[TD]252[/TD]
[TD]21[/TD]
[TD]21/20[/TD]
[/TR]
[TR]
[TD]Two pounds[/TD]
[TD]1920[/TD]
[TD]480[/TD]
[TD]40[/TD]
[TD]2[/TD]
[/TR]
[TR]
[TD]Two guineas[/TD]
[TD]2016[/TD]
[TD]504[/TD]
[TD]42[/TD]
[TD]21/10[/TD]
[/TR]
[TR]
[TD]Fifty shillings[/TD]
[TD]2400[/TD]
[TD]600[/TD]
[TD]50[/TD]
[TD]5/2[/TD]
[/TR]
[TR]
[TD]Triple unite[/TD]
[TD]2880[/TD]
[TD]720[/TD]
[TD]60[/TD]
[TD]3[/TD]
[/TR]
[TR]
[TD]Five pounds[/TD]
[TD]4800[/TD]
[TD]1200[/TD]
[TD]100[/TD]
[TD]5[/TD]
[/TR]
[TR]
[TD]Five guineas[/TD]
[TD]5040[/TD]
[TD]1260[/TD]
[TD]105[/TD]
[TD]21/4
[/TD]
[/TR]
[/TABLE]
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.
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.
[TABLE="class: grid"]
[TR]
[TD]Coin[/TD]
[TD]Farthing[/TD]
[TD]Penny[/TD]
[TD]Shilling[/TD]
[TD]Pound[/TD]
[/TR]
[TR]
[TD]Mite[/TD]
[TD]1/6[/TD]
[TD]1/24[/TD]
[TD]1/288[/TD]
[TD]1/5760[/TD]
[/TR]
[TR]
[TD]Quarter farthing[/TD]
[TD]1/4[/TD]
[TD]1/16[/TD]
[TD]1/192[/TD]
[TD]1/3840[/TD]
[/TR]
[TR]
[TD]Third farthing[/TD]
[TD]1/3[/TD]
[TD]1/12[/TD]
[TD]1/144[/TD]
[TD]1/2880[/TD]
[/TR]
[TR]
[TD]Half farthing[/TD]
[TD]1/2[/TD]
[TD]1/8[/TD]
[TD]1/96[/TD]
[TD]1/1920[/TD]
[/TR]
[TR]
[TD]Farthing[/TD]
[TD]1[/TD]
[TD]1/4[/TD]
[TD]1/48[/TD]
[TD]1/960[/TD]
[/TR]
[TR]
[TD]Halfpenny[/TD]
[TD]2[/TD]
[TD]1/2[/TD]
[TD]1/24[/TD]
[TD]1/480[/TD]
[/TR]
[TR]
[TD]Three farthings[/TD]
[TD]3[/TD]
[TD]3/4[/TD]
[TD]1/16[/TD]
[TD]1/320[/TD]
[/TR]
[TR]
[TD]Penny[/TD]
[TD]4[/TD]
[TD]1[/TD]
[TD]1/12[/TD]
[TD]1/240[/TD]
[/TR]
[TR]
[TD]Three halfpence[/TD]
[TD]6[/TD]
[TD]1 1/2[/TD]
[TD]1/8[/TD]
[TD]1/160[/TD]
[/TR]
[TR]
[TD]Twopence, half-groat[/TD]
[TD]8[/TD]
[TD]2[/TD]
[TD]1/6[/TD]
[TD]1/120[/TD]
[/TR]
[TR]
[TD]Threepence[/TD]
[TD]12[/TD]
[TD]3[/TD]
[TD]1/4[/TD]
[TD]1/80[/TD]
[/TR]
[TR]
[TD]Groat[/TD]
[TD]16[/TD]
[TD]4[/TD]
[TD]1/3[/TD]
[TD]1/60[/TD]
[/TR]
[TR]
[TD]Sixpence[/TD]
[TD]24[/TD]
[TD]6[/TD]
[TD]1/2[/TD]
[TD]1/40[/TD]
[/TR]
[TR]
[TD]Shilling[/TD]
[TD]48[/TD]
[TD]12[/TD]
[TD]1[/TD]
[TD]1/20[/TD]
[/TR]
[TR]
[TD]Florin[/TD]
[TD]96[/TD]
[TD]24[/TD]
[TD]2[/TD]
[TD]1/10[/TD]
[/TR]
[TR]
[TD]Half-crown[/TD]
[TD]120[/TD]
[TD]30[/TD]
[TD]2 1/2[/TD]
[TD]1/8[/TD]
[/TR]
[TR]
[TD]Double florin[/TD]
[TD]192[/TD]
[TD]48[/TD]
[TD]4[/TD]
[TD]1/5[/TD]
[/TR]
[TR]
[TD]Crown[/TD]
[TD]240[/TD]
[TD]60[/TD]
[TD]5[/TD]
[TD]1/4[/TD]
[/TR]
[TR]
[TD]Quarter guinea[/TD]
[TD]252[/TD]
[TD]63[/TD]
[TD]5 1/4[/TD]
[TD]21/80[/TD]
[/TR]
[TR]
[TD]Third guinea[/TD]
[TD]336[/TD]
[TD]84[/TD]
[TD]7[/TD]
[TD]7/20[/TD]
[/TR]
[TR]
[TD]Halfpound, half sovereign[/TD]
[TD]480[/TD]
[TD]120[/TD]
[TD]10[/TD]
[TD]1/2[/TD]
[/TR]
[TR]
[TD]Half guinea[/TD]
[TD]504[/TD]
[TD]126[/TD]
[TD]10 1/2[/TD]
[TD]21/40[/TD]
[/TR]
[TR]
[TD]Pound, sovereign, unite, laurel[/TD]
[TD]960[/TD]
[TD]240[/TD]
[TD]20[/TD]
[TD]1[/TD]
[/TR]
[TR]
[TD]Guinea[/TD]
[TD]1008[/TD]
[TD]252[/TD]
[TD]21[/TD]
[TD]21/20[/TD]
[/TR]
[TR]
[TD]Two pounds[/TD]
[TD]1920[/TD]
[TD]480[/TD]
[TD]40[/TD]
[TD]2[/TD]
[/TR]
[TR]
[TD]Two guineas[/TD]
[TD]2016[/TD]
[TD]504[/TD]
[TD]42[/TD]
[TD]21/10[/TD]
[/TR]
[TR]
[TD]Fifty shillings[/TD]
[TD]2400[/TD]
[TD]600[/TD]
[TD]50[/TD]
[TD]5/2[/TD]
[/TR]
[TR]
[TD]Triple unite[/TD]
[TD]2880[/TD]
[TD]720[/TD]
[TD]60[/TD]
[TD]3[/TD]
[/TR]
[TR]
[TD]Five pounds[/TD]
[TD]4800[/TD]
[TD]1200[/TD]
[TD]100[/TD]
[TD]5[/TD]
[/TR]
[TR]
[TD]Five guineas[/TD]
[TD]5040[/TD]
[TD]1260[/TD]
[TD]105[/TD]
[TD]21/4
[/TD]
[/TR]
[/TABLE]