Meaning of ARITHMETIC in English
/ əˈrɪθmətɪk; NAmE / noun [ U ]
the type of mathematics that deals with the adding, multiplying, etc. of numbers :
He's not very good at arithmetic.
sums involving the adding, multiplying, etc. of numbers :
a quick bit of mental arithmetic
I think there's something wrong with your arithmetic.
Middle English : from Old French arismetique , based on Latin arithmetica , from Greek arithmētikē (tekhnē) (art) of counting, from arithmos number.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005