Standard application of similarity method to find solutions of PDEs mostly results in reduction to ODEs which are not easily
integrable in terms of elementary or tabulated functions. Such situations usually demand solving reduced ODEs numerically.
However, there are no systematic procedures available to utilize these numerical solutions of reduced ODE to obtain the solution
of original PDE. A practical and tractable approach is proposed to deal with such situations and is applied to obtain approximate
similarity solutions to different cases of an initial-boundary value problem of unsteady gas flow through a semi-infinite porous
medium.