In this task, you are given an input list A. You need to find all the elements of the list that are numbers and calculate their sum.
['8103', '8891', '467', 'u', 'J', 'd', '8111', '2441', '4015', 'r', 'a', 'K', 'g', 'K', 'u', '1867', 'K', 'Q', '9017', 'x']