In this chapter, propagation of round-off errors in floating point arithmetic operations of computers numbers is presented. The notions of the conditional number, stability and complexity of algorithms are introduced and illustrated by examples. The Horners scheme for evaluation of Polynomials is given to elucidate the optimal and well-conditioned algorithms when they are implemented in a computer system like Mathematica. The chapter ends with a set of questions.
Keywords: Computer numbers, Round-off errors.