Fractional calculus is the subject of evaluating derivatives and integrals of non-integer orders of a given function, while fractional differential equations (considered in this work) is the subject of studying the solution of differential equations of fractional order, which contain initial conditions. The general form of a fractional differentia equation is given by: y(q) f(x, y), y(q k)(x0) y0 where k 1, 2, …, n + 1, n < q < n + 1 and n is an integer number. The solution of fractional differential equations has so many difficulties in their analytic solution, therefore numerical methods may be in most cases be the suitable method of solution. Therefore, the objective of this work is to introduce and study several approximate methods for solving fractional differential equations numerically with the cooperation of linear multistep methods for solving numerically differential equations and Riemann-Liouville formula of fractional integration .