The basic operations (addition, subtraction, multiplication,
division, power to an integer) are implemented by TeX macros in
this package. Operands may be numbers with arbitrary numbers of
digits; scientific notation is allowed. The expression scanner
is also provided. Exhaustive documentation (including detailed
TeXnical documentation) is included. The macro includes many
optimizations and uses only TeX primitives (from classic TeX)
and \newcount macro.

Homepage:
https://ctan.org/pkg/apnum
