05. Average Number

import java.util.Scanner;

public class AverageNumber {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int numberCount = Integer.parseInt(scanner.next()),
                number, sumNumbers = 0;

        for (int i = 0; i < numberCount; i++) {
            number = Integer.parseInt(scanner.next());
            sumNumbers += number;
        }

        double average = 1.0 * sumNumbers / numberCount;
        System.out.printf("%.2f\n", average);
    }
}

ИЛИ:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int numberCount = Integer.parseInt(scanner.next()), sumNumbers = 0;

        for (int i = 0; i < numberCount; i++) {
            sumNumbers += Integer.parseInt(scanner.next());
        }

        System.out.printf("%.2f\n", (double) sumNumbers / numberCount);
    }
}