find the sum of the multiples of 3 and 5 below 1000

Question

Ok guys, so I\'m doing the Project Euler challenges and I can\'t believe I\'m stuck on the first challenge. I really can\'t see why I\'m getting the wrong answer despite my

Answer 1

Okay, so this isn't the best looking code, but it get's the job done.

public class Multiples {

public static void main(String[]args) {
    int firstNumber = 3;
    int secondNumber = 5;
    ArrayList numberToCheck = new ArrayList();
    ArrayList multiples = new ArrayList();
    int sumOfMultiples = 0;
    for (int i = 0; i < 1000; i++) {
       numberToCheck.add(i);

       if (numberToCheck.get(i) % firstNumber == 0 || numberToCheck.get(i) % secondNumber == 0) {
           multiples.add(numberToCheck.get(i));
       }

    }

    for (int i=0; i