private void drawNumbers(Graphics g){
        for (int x = 0, i = 0; x < 400 && i<9; x += 40) {
            for (int y = 40, j=0; y < 400 && j < 9; y += 40) {
                if(sudokuArray[j][i]!= 0){
                    g.drawString(sudokuArray[j][i]+"", x + 15, y - 12);
                }
                j++;
            }
            i++;
        }
    }