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.
['7075', '7033', 'V', 'y', 'M', 'b', 'q', '1745', 'w', 'L', '5921', '8617', '8383', 'U', '1133', 'W', '547', 'U', '1741', '5215']