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.
['1007', '4759', 'F', 'j', 'x', 'T', 'y', 'C', '7909', '1347', '7865', '9447', '7237', '1509', '6695', 'a', '9847']