I. arith·me·tic əˈrithməˌtik noun
( -s )
Etymology: alteration (influenced by Greek arithmētikē ) of earlier arithmetrik, from Middle English, alteration (influenced by Latin arithmetica or Greek arithmētikē ) of arsmetrike, modification (influenced by Latin ars art & Latin metricus of measurement) of Old French arismetique, from Latin & Greek; Latin arithmetica, from Greek arithmētikē, from feminine of arithmētikos arithmetical, from arithmein to count, from arithmos number — more at arithmo- , art , metric
1.
a. : the branch of mathematics that treats of the properties and relationships of real numbers and of computations with them involving chiefly addition, subtraction, multiplication, and division
b. : a textbook or treatise on the principles of arithmetic
2. : application of arithmetic : computation , calculation , reckoning
your arithmetic is pretty bad
he jogged himself into an arithmetic of the number of nips of liquor he had taken — George Meredith
II. ar·ith·met·ic |a(ˌ)rith|med.ik, -_rəth-, -etik, -ēk also |e- adjective
or ar·ith·met·i·cal -ə̇kəl, -ēk-
1. : of or relating to arithmetic : in agreement with the rules or methods of arithmetic
2. : proceeding by an arithmetic progession ; especially : having equal spacing between divisions corresponding to successive positive or negative integers
arithmetic scale
• ar·ith·met·i·cal·ly -ə̇k(ə)lē, -li adverb