What's wrong with my method? Addition isn't working, always printing 0

public static void main(String args[])
{
    LinkedHashMap<String,Integer> map = new LinkedHashMap<String,Integer>();
    Scanner scan = new Scanner(System.in);

    while(scan.hasNextLine())
    {
        String line = scan.nextLine();
        String[] tokens = line.split(" ");

        if(!Character.isDigit(tokens[0].charAt(0)) && !line.equals("clear") && !line.equals("var"))
        {
            int value = 0;
            for(int i=0; i<tokens.length; i++)
            {
                if(tokens[i].charAt(0) == '+')
                {
                    addition(tokens, value);
                    break;
                }

                else if(i==tokens.length-1)
                {
                    System.out.println("No operation");
                    break;
                }
            }
            map.put(tokens[0], value);
            System.out.println(map);
        }       

        if(line.equals("clear"))
        {
            clear(map);
        }
        if(line.equals("var"))
        {
            variableList(map);
        }       
    }
}

public static int addition(String[] a, int b)
{
    for(int j=0; j<a.length; j++)
    {
        if(Character.isDigit(a[j].charAt(0)))
        {
            int add = Integer.parseInt(a[j]);
            b = b + add;
        }   
    }
    return b;
}

I had this working all in the main method, but I wanted to separate it to make it cleaner. I must've done something wrong because now the addition method doesn't even function properly. For example, a = 5 + 6 should print the map {a=11}