. Create the logic for a program that performs arithmetic functions. Design the program to contain two numeric variables, and prompt the user for values for the variables. Pass both variables to methods named sum() and difference(). Create the logic for the methods sum() and difference(); they compute the sum of and difference between the values of two arguments, respectively. Each method should perform the appropriate computation and display the results. b. Modify the program in Exercise 5a so that the two entere