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.
['Y', '325', '4917', '7127', 't', 'M', 'd', 'Q', 'V', '7273', '7089', 'Z', '3081', '5413', 'A', 'W', '7845', '2113', '8007', 'Z']