65L05 Initial value problems
65L06 Multistep, Runge-Kutta and extrapolation methods
65L07 Numerical investigation of stability of solutions
65L08 Improperly posed problems 
65L09 Inverse problems
65L10 Boundary value problems
65L12 Finite difference methods
65L15 Eigenvalue problems 
65L20 Stability and convergence of numerical methods
65L50 Mesh generation and refinement
65L60 Finite elements, Rayleigh-Ritz, Galerkin and collocation methods
65L70 Error bounds 
65L80 Methods for differential-algebraic equations
65L99 None of the above, but in this section