what am i doing wrong? I don't know what my final sum should be.

[amyissmartical]

import java.util.Scanner;
import java.text.DecimalFormat;
public class Burger
{
static Scanner console = new Scanner (System.in);
public static void main (String [] args)
{
double sum = 0;
for (int week = 1; week <= 4; week = week+1)
{
System.out.print("How many hours did you work in week " + week + "? ");
int h = console.nextInt();
DecimalFormat d = new DecimalFormat ("0.00");
double weeklypayment = (h*5.15) - (h * 5.15 * 0.3);
System.out.println("Your take-home pay is $" + d.format(weeklypayment));
}

System.out.println();
sum = sum + weeklypayment;
DecimalFormat d = new DecimalFormat ("0.00");
System.out.println("Your total pay for the month is $" + d.format(sum));
System.out.println ("Hope you enjoy working at Babbage Burgers.");
}
}

[DiamondSoul]

For future reference, please use [code] tags when posting source code - makes it much more readable.

Your problem is that you need to add the weekly payment inside the for loop, so it adds all four weekly payments. Take this line of code:

sum = sum + weeklypayment;

and move it inside the for loop.