A box contains four slips of paper marked 1, 2, 3, and 4. Two slips are selected

Question:

A box contains four slips of paper marked 1, 2, 3, and 4. Two slips are selected without replacement. List the possible values for each of the following random variables:
a. x = sum of the two numbers
b. y = difference between the first and second numbers ( first 2 second)
c. z = number of slips selected that show an even number
d. w = number of slips selected that show a 4