This kata is intented to exercise your developing skills and show what you are capable of. Some interesting topics to you to considered:

• Object Oriented Design (class, abstract, Interface, override, access permissions, inheritance, polymorphism);
• C# and dotnet features (extension method, reflection, dynamic, lambda, delegate, Linq, C# 7, Exception Handling, generic, Variance/Covariance, Task, await, async);
• Agile patterns, principles and practices in Agile (Craftsmanship);
• Solution architecture and derivablity;
• Testability and quality strategies;
• Documentation capability: it should be easy to understand your desing/architecture choises and how it should function;
• We like web applications, cosider doing one, UX isn't a issue here;
• Write this application as you would deliver to production, not as a demo;

As a student
I want to post a fatorial calculus with add and mutiple operations
In order to validate its result

• The fatorial calculus should accept add and mutiple operation;
• Mutiplication should precede addition;
• Be able to reinforce precedence by using parentheses;
• All open parentheses should have other to close;