It is the belief of Old Babylonian scholars, such as Ettore Carruccio, that Old Babylonians "seem to have used the abacus for the operations of addition and subtraction; however, this primitive device proved difficult to use for more complex calculations".
ɪɾ ɪz ðə bᵻlˈiːf ʌv ˈoʊld bˌæbɪlˈoʊniən skˈɑːlɚz, sˈʌtʃ ɐz ˈɛɾɚ kæɹˈuːtʃɪˌoʊ, ðæt ˈoʊld bˌæbɪlˈoʊniənz "sˈiːm tə hæv jˈuːzd ðɪ ˈæbækəs fɚðɪ ˌɑːpɚɹˈeɪʃənz ʌv ɐdˈɪʃən ænd sʌbtɹˈækʃən; haʊˈɛvɚ, ðɪs pɹˈɪmᵻtˌɪv dɪvˈaɪs pɹˈuːvd dˈɪfɪkəlt tə jˈuːz fɔːɹ mˈoːɹ kˈɑːmplɛks kˌælkjʊlˈeɪʃənz".