Sentence:  We may there find some slight attempts at a study of literature, but mathematics was never read: to learn the use of the <WSD>abacus</WSD>, to keep accounts, and to know the rule by which the date of Easter could be determined was all the science that the most studious aimed at. 
Meaning of the word marked with <WSD> tags:  A calculating table or frame; an instrument for performing arithmetical calculations by balls sliding on wires, or counters in grooves, the lowest line representing units, the second line, tens, etc. (First attested in the late 17th century.)<ref name=SOED>(page=2)</ref>