higher arithmetic

noun2

1. •
   (old-fashioned) Number theory; the branch of pure mathematics concerned primarily with integers and integer-valued functions.

   • The higher arithmetic, or the theory of numbers, is concerned with the properties of the natural numbers 1, 2, 3, . . . . — 1999
2. •
   (no longer used) A loosely defined range of topics in arithmetic, distinguished from elementary arithmetic by the more advanced nature of the methods and concepts.

   • With division higher arithmetic naturally begins, and for the more advanced pupil it will be proper here to insert a short course on that subject. — 1976