Thread: Math operations not working..

Hey, I'm having a bit of trouble with math operators which should work but don't.

class Assignment10
{
	//constructor with 8 parameters to initialize the variables
	Assignment10(int markQuiz1, int markQuiz2, int markQuiz3, int markQuiz4, int markQuiz5, int markMidterm, int markFinExam, String studentName)
	{
		//Calculates the grade percentages and then finds out the final grade for the class.
 
 
		double markQuizesFinal = (((markQuiz1 + markQuiz2 + markQuiz3 + markQuiz4 + markQuiz5) / 50) * 100);
		double markFinal_D = 5.7; //Temp testing value, don't pay any attention to this
		double decimalPlace = (markFinal_D % 1);
 
		if (decimalPlace >= 0.51) // Determines if the final mark should be rounded up or down and then rounds it up or down to get a more precise mark.
		{
			markFinal_D = (markFinal_D - decimalPlace);
			markFinal_D = (markFinal_D + 1);
		}
		else
			markFinal_D = (markFinal_D - decimalPlace);
 
		int markFinal_I = 0; //Initilizes markFinal_I and sets it to 0 so the program will compile properly.
		markFinal_I = (int)markFinal_D; //Casts the double markFinal_D to the interger variable markFinal_I
 
		//Prints the final grade in both numerical and letter format.
		System.out.print(""+studentName+"'s final Grade is:");
		System.out.print(" "+markFinal_I+" ");
		System.out.print(" "+markQuizesFinal+" ");
 
		if (markFinal_I >= 90.0) //Determines and sets the letter grade for the student depending on their mark.
			System.out.print("A");
		else if (markFinal_I >= 80.0 && markFinal_I < 90.0)
			System.out.print("B");
		else if (markFinal_I >= 70.0 && markFinal_I < 80.0)
			System.out.print("C");
		else if (markFinal_I >= 60.0 && markFinal_I < 70.0)
			System.out.print("D");
		else if (markFinal_I < 60.0)
			System.out.print("F");
 
		System.out.println("");
	}
}	
 
	// Test Class
 
	class Assignment10Tester
	{
		public static void main (String[] args)
		{
			Assignment10 bob = new Assignment10(3, 4, 6, 2, 7, 70, 54, "bob");
			Assignment10 celestia = new Assignment10(9, 8, 7, 6, 5, 97, 85, "celestia");
		}
	}

The line that has the 'broken?' math operators in line number 9. I've done the same operation in a calculator and it does work but for some reason it's not working here.