Someone

    int right_answer[];
    right_answer = new int[rounds];
    
    for (int i = 0; i < rounds; i++)
    {
        choise = dump.nextInt(4); 
                
        r_number1 = dump.nextInt(11);
        r_number2 = dump.nextInt(11);
        
        System.out.print("Omgång " + (i+1) + ": " + r_number1 + counts[choise] + r_number2 + " = ");
        answer = scan.nextInt();          
        
        user_answer[i] = ""+answer+"";
        
        switch (choise) {
            case 0: right_answer[i] = r_number1 + r_number2; break;
            case 1: right_answer[i] = r_number1 - r_number2; break;
            case 2: right_answer[i] = r_number1 * r_number2; break;
            case 3: right_answer[i] = r_number1 / r_number2; break;
        }
    }