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.
['D', 'I', 'Q', '7451', '2025', '9155', 'r', '5057', '1513', 'B', '8223', 'v', '5411', '9635', 'g', '2915', 'y', 'w', 'w']