title: Unable To Find A Constructor
body: <p><a href="https://i.stack.imgur.com/kFcLA.jpg" rel="nofollow noreferrer">ScreenShot Of Error</a> i have a json file which contains some data and i want to parse it but every time when i want to Deserialize Object it give me this error "Unable to find a constructor. A Class should either have a default constructor, one constructor with arguments or a constructor marked with json constructor i dont know what to do because i did not work with json before it is my first time working with json. 
  here is my json :</p>
  
  <pre><code>{
     "Addition":
     {
         "Easy": [
  
                  "New York Bulls",
                  "Los Angeles Kings",
                  "Golden State Warriros",
                  "Huston Rocket"
              ],
        "Medium":[
                  "New York Bulls",
                  "Los Angeles Kings",
                  "Golden State Warriros",
                  "Huston Rocket"
        ],
         "Difficult": [
                 "New York Bulls",
                 "Los Angeles Kings",
                 "Golden State Warriros",
                 "Huston Rocket"
        ] 
     }
  }
  </code></pre>
  
  <p>here is my model class</p>
  
  <pre><code>public class Addition
  {
  
       public List&lt;string&gt; Easy { get; set; }
          public List&lt;string&gt; Medium { get; set; }
          public List&lt;string&gt; Difficult { get; set; }
  
      public Addition() { }
  
  }
  </code></pre>
  
  <p>here is my function in which i am Deserialize object</p>
  
  <pre><code>private void ReadJson()
      {
          var assembly = typeof(WordProblemsScreen).GetTypeInfo().Assembly;
          Stream stream = 
  assembly.GetManifestResourceStream("MathRandomizer.demo.json");
  
          using (var reader = new System.IO.StreamReader(stream))
          {
  
              string json = reader.ReadToEnd();
  
              JObject jObject = JObject.Parse(json);
              JToken jUser = jObject["Addition"];
  
  
              var addition = JsonConvert.DeserializeObject&lt;Addition&gt;(json);
  
  
  
  
          }
      }
  </code></pre>