Calling a dll from .NET allpication

Add reference of that dll in needed project by right clicking on that project, select a "Add a Reference " from context menu

An Add Reference pop up will prompt you navigate to that dll. Browse that Dll.and add it into project

now add namespace in needed file, by using "Using" keyword

create an object of the class in which that method is defined

call the method using oject created.

pass required parameter, get the result.

Add reference of that dll and then write
using namespace of that dll in your form
and then call proper method or variables whatever of your dll
you just have to pass parameter of two numbers to that dll

just visit my article here a have created dll in vb.net u have to create c# other wise all functionality are same.
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