Number Analysis                                                                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                                                                                                                                      source                                                                                                                                         
                                                                                                                                                                                                                                                                                     
                                                              a                                                                                                  b                                                                                                                 c 
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                     
                        case1                                                                                                     case2                                                                                                      case3