Roman and East Asian abacuses use a system resembling bi-quinary coded decimal, with a top deck (containing one or two beads) representing fives and a bottom deck (containing four or five beads) representing ones.
ɹˈoʊmən ænd ˈiːst ˈeɪʒən ˈæbɐkəsᵻz jˈuːs ɐ sˈɪstəm ɹᵻzˈɛmblɪŋ bˈaɪkwˈɪnɚɹi kˈoʊdᵻd dˈɛsɪməl, wɪð ɐ tˈɑːp dˈɛk kəntˈeɪnɪŋ wˈʌn ɔːɹ tˈuː bˈiːdz ɹˌɛpɹᵻzˈɛntɪŋ fˈaɪvz ænd ɐ bˈɑːɾəm dˈɛk kəntˈeɪnɪŋ fˈoːɹ ɔːɹ fˈaɪv bˈiːdz ɹˌɛpɹᵻzˈɛntɪŋ wˌʌnz.