Vigesimal

Vigesimal system is a base-20 numeral system used in many cultures.
The vigesimal system is a remnant of the Paleo-Balkan Indo-European tribes and their language.
In Albanian, the vigesimal system coexists with the decimal system, reflecting the contribution of Pre-Indo-European people.
In Basque, the vigesimal system is used for numbers up to 100, with words for 40, 60, and 80 meaning «two-score», «three-score», and «four-score», respectively.
In the £sd currency system, there were 20 shillings to the pound, and the shilling coins were re-valued at 5 pence.
In the imperial weight system, there are twenty hundredweight in a ton.
In English, the cardinal number 20 is commonly phrased with the word ‘twenty’.

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