https://coinweek.com/world-coi...ation-day-in-the-uk/

"The old duodecimal system, while based on the pound, was quite inefficient and made accounting difficult. For hundreds of years, two farthings equaled a half penny; two half pennies made a penny; two threepence made one sixpence; two sixpence were a shilling; five shillings a crown; and four crowns made a pound. Basically, one pound was equal to 240 pennies and one shilling was equal to 12 pennies."