The abacus (: abaci or abacuses), also called a counting frame, is a hand-operated calculating tool of unknown origin used since ancient times in the ancient Near East, Europe, China, and Russia, millennia before the adoption of the Hindu-Arabic numeral system.
ðɪ ˈæbækəs: ˈæbɐsˌaɪ ɔːɹ ˈæbɐkəsᵻz, ˈɔːlsoʊ kˈɔːld ɐ kˈaʊntɪŋ fɹˈeɪm, ɪz ɐ hˈændˈɑːpɚɹˌeɪɾᵻd kˈælkjʊlˌeɪɾɪŋ tˈuːl ʌv ʌnnˈoʊn ˈɔːɹɪdʒˌɪn jˈuːzd sˈɪns ˈeɪntʃənt tˈaɪmz ɪnðɪ ˈeɪntʃənt nˌɪɹ ˈiːst, jˈʊɹɹəp, tʃˈaɪnə, ænd ɹˈʌʃə, mɪlˈɛniə bᵻfˌoːɹ ðɪ ɐdˈɑːpʃən ʌvðə hˈɪnduːˈæɹɐbˌɪk nˈuːmɚɹəl sˈɪstəm.