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.
['7067', 'E', 'C', '1879', 'Z', 'u', 't', '2053', '6769', 'r', '5207', '7009', 'H', '5587', 'i', 'M', '1357', 'A']