Your 12 and 20 are the wrong way round.
Amusingly when the UK decimalized its currency in 1971, 1 (old) penny was approximately worth 1 cent. In 2022, 1 (new) penny is approximately worth 1 cent.
Unfortunately for the Brits, that means £1=$2.40 in 1971 but £1=$1 in 2022.
The still sell horses in guineas: 1 guinea = 21 shillings = £1.10.
When Australia decimalized the government (when? I diunno) took a different route. They changed from pounds, shillings and pence to dollars and cents with AUS$2 = AUS£1, so pennies and cents were roughly equivalent.
I was working in Finland when they switched from markka to euros. That was fun!