using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var json = "{\"calculations\":{\"net\":{\"1\":\"0.1\"}}}";

        var deserialized = JsonConvert.DeserializeObject<Json>(json);

        Console.WriteLine(deserialized.Calculations.Net._1);

    }

    public record Json(Calculation Calculations);

    public record Calculation(Net Net);

    public record Net([property:JsonProperty("1")]string _1);

}