Number Analysis                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                       
                                                                                                                                        source                                                                                                                                         
                                                                                                                                                                                                                                                                                       
                                                                a                                                                                                                                                                                                                    c 
                                                                                                                                                                   b                                                                                                                   
                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                       
                          case1                                                                                                     case2                                                                                                      case3