There is a possibility of contradiction as you have declared a variable squares which is further declared as function parameter. So it is incrementing the value once by taking the class variable.

Use the given code:

     public class d55 {
        int squares = 81;
        public static void main(String[] args) 
        {
            new d55().go();
    }
    void go(){

       int num= incr(++squares);
        System.out.println(num);
    }

    int incr(int squares){

        int num=squares += 10;
        return num ; 
    }
}

Thanks...