  A unified explicit form for difference formulas to approximate the fractional
and classical derivatives is presented. The formula gives finite difference
approximations for any classical derivatives with a desired order of accuracy
at nodal point in the computational domain. It also gives Gr\"unwald type
approximations for fractional derivatives with arbitrary order of approximation
at any point. Thus, this explicit unifies approximations of both types of
derivatives. Moreover, for classical derivatives, it provides various finite
difference formulas such as forward, backward, central, staggered, compact,
non-compact etc. Efficient computations of the coefficients of the difference
formulas are also presented that lead to automating the solution process of
differential equations with a given higher order accuracy. Some basic
applications are presented to demonstrate the usefulness of this unified
formulation.

Numerical Analysis;Numerical Analysis