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.
['1153', '2543', '7237', 'B', '8425', '6245', 't', 'o', 'F', 'h', '2637', 'w', '623', 'Q', 'J', '6151', 'Y', 'K', '9247']