KiloToMiles.java

public class KiloToMiles {

    public static void main(String[] args) {
        double kilometers = 5;//สมมติเป็น 5 กิโลเมตร
        double miles = kilometers / 1.609;

        System.out.println(miles);

    }
}

NumberReverse.java

public class NumberReverse {

    public static void main(String[] args) {
        int number = 123;
        int number1 = number / 100;
        int number2 = number % 100 / 10;
        int number3 = number % 10;

        System.out.println(number3 + "" + number2 + "" + number1);

    }
}

StudentIdThreeDigits.java

public class StudentIdThreeDigits {

    public static void main(String[] args) {
        long studentId = 60130803344L;
        System.out.println(studentId%1000);
    }
}