The package provides basic arithmetic operations to 8 decimal
places for plain TeX or LaTeX. Results are exact when they fit
within the digit limits. Along with the basic package is an
optional extension that adds computation of sin, cos, log,
sqrt, exp, powers and angles. These are also exact when
theoretically possible and are otherwise accurate to at least 7
decimal places. In addition, the package provides a stack-based
programming environment.

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