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.
['2109', 'G', '309', 'j', '7611', 'X', 'v', '9941', '5549', '7195', 't', '6669', 'Z', 'g', 'L', '2923', 'o', '6579', '4277', 'h']