The theory is explained in simplest way and finding the numerical solutions for several methods has been treated in detail and illustrated by large number of numerical examples. Table Of Contents: 1. ERRORS AND THEIR ACCURACY2. CURVE FITTING3. SOLUTIONS OF SIMULTANEOUS LINEAR SYSTEM OF EQUATIONS4. SOLUTION OF ALGEBRIC AND TRANSCENDENTAL EQUATIONS5. FINITE DIFFERENCES AND INTERPOLATION6. NUMERICAL DIFFERENTAITION7. NUMERICAL INTEGRATION8. NUMERICAL SOLUTION OF ORDINARY DIFFERENTIAL EQUATIONS