65M06 Finite difference methods 
65M12 Stability and convergence of numerical methods 
65M15 Error bounds 
65M20 Method of lines 
65M25 Method of characteristics 
65M30 Improperly posed problems 
65M32 Inverse problems 
65M50 Mesh generation and refinement 
65M55 Multigrid methods; domain decomposition 
65M60 Finite elements, Rayleigh-Ritz and Galerkin methods, finite methods 
65M70 Spectral, collocation and related methods 
65M99 None of the above, but in this section