This Book shows how the scientific methods can be applied for engineering courses. After short introduction into the numerical methods, MATLAB, MAPLE and MuPAD have been chosen as Computer Programs. Codes have been written using these programs for practical examples. The codes of each chapter can be downloaded from http://pubwww.hsz- t.ch/gapaydin/SCcodes. This book includes some of fundamental methods of: Nonlinear Equations, Linear Systems, Interpolation, Differentiation, Integration, Optimization, Differential Equations, and Eigenvalues with Eigenvectors.