how to consume these library project into web api and i also add a reference to web api

''' problem statement : consume class library into web api and expose web api

this is LibraryProject("CalculatorLibrary").And i add a dll file as reference to my web api(CalculatorWebApi ). i didn't know how to write the code inside web api controller inorder to access the methods in calculatorlibrary

using System.Collections.Specialized;
namespace CalculatorLibrary
{
    public class Calculator
    {
        public static int Add(int num1,int num2)
        {
            return num1 + num2;
              }
        public static int Sub(int num1, int num2)
         {
            return num1 - num2;
              }
       public static int Mul(int num1, int num2)
        {
         return num1 * num2;
             }
      public static int Div(int num1, int num2)
        {
          return num1 / num2;
             }

'''

''' this is web api controller(CalculatorWeApiController)

 using CalculatorLibrary;
 using System;
 namespace CalculatorWebApi.Controllers
  {
       [Route("api/[controller]")]
       [ApiController]
       public class CalculatorController : ControllerBase
        {
   
            }
       }

'''