Computer (symbolic) algebra systems and libraries are used for manipulations with symbolic mathematical expressions.
Usually, those libraries are capable of some calculus operations (differentiation, integration, finding the limit, etc.) and numeric manipulations.
The idea is to avoid floating number operations by computing the exact result instead.
FLINT (Fast Library for Number Theory)
Library for Polynomial System Solving through Algebraic Methods
Programming language for symbolic computation with unusual combination of pattern matching features: Tree patterns, associative patterns and expressions embedded in patterns.
General purpose math library with primarily arithmetic functions.
A library for computing modular GCD of univariate polynomials.
C.Algebra System derived fron own Author works.
Rust low-level and high-level bindings for GMP-ECM.
Experimental CAS in C
arithmetic in (small) finite fields