Showing a letter for a grade average

Code:

import java.util.Scanner;
 
public class Grades {
   public static void main(String[] args) {
 
      char grades[] = {'F','D','C','B','A'};
 
      System.out.print("Enter final class average: ");
 
      // Read in final class average
      Scanner in = new Scanner(System.in);
      double average = in.nextDouble();
 
      char grade = grades[(int)Math.min(4,Math.max(0,((average-1)/10)-5))];
      System.out.println("Grade: " + grade);
   }
}

Output:

$ java Grades
Enter final class average: 98
Grade: A

$ java Grades
Enter final class average: 71
Grade: C

$ java Grades
Enter final class average: 82
Grade: B