For 5-adic numbers, see p-adic number. For the pental numeral system, see Quinary.
Edward Larsson's notes from 1885 show the use of "pentadic" runic numerals to replace the Arabic numerals in representing dates. The number shown here as zero is normally used for ten.
Pentadic numerals (Swedish: pentadiska siffror) are a notation for presenting numbers, usually by inscribing in wood or stone. The notation has been used in Scandinavia, usually in conjunction with runic calendars and inscriptions in runes.