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.
['1485', '7923', '1485', '3319', 'a', '9483', '6237', 'v', 'n', 'j', 'i', '2645', 'd', 'X', 'T', '4503', '7735', 'q']