In this program, you can use the Select Case ......End Select statement to determine whether a number entered by a user is a prime number or not. For case 1, all numbers that are less than 2 are prime numbers. In Case 2, if the number is 2, it is a prime number. In the last case, if the number N is more than 2, we need to divide this number by all the numbers from 3,4,5,6,........up to N-1, if it can be divided by any of these numbers, it is not a prime number, otherwise it is a prime number. To control the program flow, we can use the Do......Loop While statement . Besides, we need to tag="Not Prime' to identify the number that is not prime, so that when the routine exits the loop, the label will display the correct answer.