In the following characters are chosen from the set of 26 letters, the set of 10 digits, or the set of 4 special characters. 1. How many subsets of the set of digits with odd cardinality are there? 2. How many subsets of the set of digits with even cardinality are there? (Empty set has even cardinality.) 3. How many ways are there to have 5 letters followed by 3 digits without any repetition among the letters or digits