public static void addition()
{
int user_int = 1;
Random rand = new Random();
Scanner scan = new Scanner(System.in);
``if (user_int == 1)``
{
``int num1 = (int) (Math.random() * 10);``
``int num2 = (int) (Math.random() * 20);``
``System.out.println("What is " +num1+ "+" +num2+ "?");``
``int answer = scan.nextInt();``
}
``else if (answer == num1 + num2) //error is occurs under "answer, num1, num2"``
{
}
``else``
{
``System.out.print("Try again: ");``
``scan.nextInt();``
}
}
