how to post JSON obj with attribute, to an API url using PHP? -

really stumped @ how approach - need to:

take json data attribute, php post api/url. should have json file in folder, file call url , pass json? how can return calculation results via json? learn this, have array of numbers, perform calculations return mean, median, mode, , range. working files need available api.

sample json data post: { "numbers": [ 5, 6, 8, 7, 5 ] } 

sample json return response single endpoint called "/mmmr" [abbrev calculations]:

{   "results": {   "mean": 6.2,   "median": 6,   "mode": 5,   "range": 3    } } 

been searching, trying things hours, not clicking @ all. have class calculate call , returns results calculations already, how "make available via api"? please sample working code, perhaps can understand seeing it.