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.
['1829', 'f', 'y', '7419', 'q', '5005', '7563', '6469', '9679', 'D', 'f', 'G', '7147', 'j', '5979', 'k', 'q', 'C', '8135', '1263']