The finite difference method (FDM) is an approximate method for solving partial differential equations. The three most widely used numerical methods to solve PDEs are the finite element method (FEM), finite volume methods (FVM) and finite difference methods (FDM), as well other kind of methods called meshfree methods, which were made to solve problems where the aforementioned methods are limited. That's all I could find on the internet. Can you help me how they work and which ones are the best?