Questions about implementing elementary arithmetic operations on a computer with hardware or algorithms. The numbers are often assumed to be in a binary representation, add the [floating-point] tag for arithmetic operations on numbers in a floating point representation.
Computer Arithmetic, a subset of Computer Architecture, deals with methods of representing integers and real values (e.g., fixed- and floating-point numbers) in digital systems and efficient algorithms for manipulating such numbers by means of hardware circuits or software routines.
On the hardware side, various types of adders, subtractors, multipliers, dividers, square-rooters, and circuit techniques for function evaluation are considered.
Software aspects of computer arithmetic include complexity, error characteristics, stability, and certifiability of computational algorithms.
Reference and further learning: https://www.ece.ucsb.edu/~parhami/pubs_folder/parh02-arith-encycl-infosys.pdf