ARITHMETIC:
Prior to the tenth century arithmetic was essentially the art of computation. It was largely devoted to computing Easter, so the terms “Computus” and “Arithmetic” became synonymous.[460] Apart from this practical side it is possible that a theoretical treatment of numbers was not absolutely wanting. The method of reckoning was necessarily crude and little progress was possible while the cumbersome Roman system of notation made computation with large numbers well nigh impossible. It remains for further investigation to show whether the arithmetical knowledge of the Irish monks extended beyond the limits of Bede’s De Tempora Ratione,[461] or equalled that of the Liber de Computo[462] of Rabanus Maurus. Our acquaintance with source material in this field is too limited to warrant any sweeping statement, but it is significant of the nature of arithmetical knowledge of this period and of the lack of creative ability to find a scholar of such ability as Marianus Scottus in the following century basing his work on Computus[463] on that of Rabanus. Indeed it was not until the introduction of the Arabic system of notation and Hindoo methods through Arabic influence that there was much possibility of progress in Arithmetic. The introduction of the Arabic system is attributed by some to Gerbert[464] (d. 1003 A.D.) but it was not until the end of the twelfth century that the Hindoo-Arabic system became generally established among mathematicians. A century later Arithmetic began to be applied to commerce.[465]
Algebra was apparently unknown to the Irish monks during the period under investigation and was probably not introduced into Europe until the twelfth century.[466]