Is there a way that I can cast the variables in my Java program so that I get a double output?

I am a beginner in Java and I am being asked to write a program to find the average of three grades. I am trying to figure out how to get a double output by type casting but I don't know where to cast. I have already written some code myself but the grader is still saying I'm not getting the right answer.

Here are the program instructions:

> In the code below, type in three made up int grades and then sum and
> average them. Use casting to report the result as a double. For
> example, if the grades are 90, 100, and 94, the sum of the three
> numbers is 90 + 100 + 94 = 284, and the average is the sum 284 divided
> by 3 which casted to a double is 94.666667. You should use your
> variables instead of the numbers in your formulas. Follow the
> pseudocode below.
>
> Type in three made up int grades and then sum and average them. Use
> type casting to report the result as a double.

Here is my code:

public class Challenge1_6
{
   public static void main(String[] args)
   {
      // 1. Declare 3 int variables called grade1, grade2, grade3
      // and initialize them to 3 values
       int grade1 = 78;
       int grade2 = 95;
       int grade3 = 84;
      // 2. Declare an int variable called sum for the sum of the grades
       int sum;
      // 3. Declare a variable called average for the average of the grades
       int average;
      // 4. Write a formula to calculate the sum of the 3 grades (add them up).
       sum = grade1 + grade2 + grade3;
      // 5. Write a formula to calculate the average of the 3 grades from the sum using division and type casting.
       average = sum / 3;
      // 6. Print out the average
       System.out.println(average);
   }
}

This is my output (It wants a decimal but I don't know how to get it):

enter image description here

Well the average variable must be double
and you cast the division result to fit in the average variable

    double average;
    // 4. Write a formula to calculate the sum of the 3 grades (add them up).
    sum = grade1 + grade2 + grade3;
    // 5. Write a formula to calculate the average of the 3 grades from the sum using division and type casting.
    average = (double) sum / 3;
    System.out.println(average);

Simply change the variable "average" to double.

double average=Double.valueOf(sum / 3);

Logic is:
At least one variable in the function (a/b) should be the type of double
Or we need to convert the int value to Double as required.

You can simply divide by the double literal 3.0 or 3d so that it performs floating point division instead of instead divison.

double average;
sum = grade1 + grade2 + grade3;
average = sum / 3.0;

Demo!

Just convert the average to double to avoid any missing due to the cast from double to int

public class Challenge1_6 {
   public static void main(String[] args) {
       int grade1 = 78;
       int grade2 = 95;
       int grade3 = 84;
       int sum;
       double average;
       sum = grade1 + grade2 + grade3;
       average = sum / 3;
       System.out.println(average);
   }
}