Webapi Application Impelimenting Dependency injection

I am learning to implement DI and Pattern in my application and I have created some requirements for myself Wrote a WebAPI application with a bunch of end points.

POST - /api/math/AddTogether Take a JSON / XML object… { values: [1,2,3,4,5,6,7,8,9] } Return { “value” : 45}

POST - /api/math/EvenNumbers Take a JSON / XML object… { values: [1,2,3,4,5,6,7,8,9] } Return { “values” : [2,4,6,8] }

GET - /api/math/GetRange/{first}/{second} {first} and {second} are values. If I were to pass /5/10 I’d expect… { “values”: [5,6,7,8,9,10] }

Trying to Make use of a service/provider layer Dependency injected Created unit tests to test your service layer with different values.

In this process my DI is looking no use for what I did and please suggest me how can I use it for better as I am new to it.My unit tests are working and application is working but I don't see any use of DI to my IInputService as there are no dependencies.

My Math controller

[RoutePrefix("api/math")]
public class MathController : ApiController
{
    private readonly InputService _inputService;

    public MathController(InputService inputService)
    {
        _inputService = inputService;
    }

    //api/math/add/
    [HttpPost]
    [Route("Add")]
    public IHttpActionResult AddTogether([FromBody] int[] numArray)
    {
        if (numArray == null)
        {
            return NotFound();
        }
        var result = _inputService.AddValues(numArray);
        return Ok(new
        {
            value = result
        });
    }

    //api/math/even/
    [HttpPost]
    [Route("Even")]
    public IHttpActionResult EvenNumbers([FromBody] int[] numArray)
    {
        if (numArray == null)
        {
            return NotFound();
        }
        var result = _inputService.EvenNumbers(numArray);
        return Ok(new
        {
            value = result
        });
    }

     //api/math/range/?firstVal=5&secondVal=10
    [HttpGet]
    [Route("Range")]
    public Number GetRange(int firstVal, int secondVal)
    {
        var range = _inputService.GetRange(firstVal, secondVal);
        return new Number
        {
            Numbers = range
        };
    }

}

DI Implementation

`public class IocConfig
{
    public static void RegisterIoc(HttpConfiguration config)
    {
        var kernel = new StandardKernel(); // Ninject IoC
        //kernel.Load(Assembly.GetExecutingAssembly()); //only required for asp.net mvc (not for webapi)
        // These registrations are "per instance request".
        // See http://ift.tt/2h8VEZA

        kernel.Bind<IInputService>().To<InputService>();


        // Tell WebApi how to use our Ninject IoC
        config.DependencyResolver = new NinjectDependencyResolver(kernel);
    }
}

IInputService

 public interface IInputService
{
    int AddValues(int[] numInts);
    List<int> EvenNumbers(int[] numInts);
    List<int> GetRange(int firstVal, int secondVal);
}

public class InputService : IInputService
{
    public int AddValues(int[] numInts)
    {
        var total = numInts.Sum();
        return total;
    }

    public List<int> EvenNumbers(int[] numInts)
    {
        var evens = new List<int>();
        foreach (var num in numInts)
        {
            if (num % 2 == 0)
            {
                evens.Add(num);
            }

        }
        return evens;
    }

    public List<int> GetRange(int firstVal, int secondVal)
    {
        IEnumerable<int> range;
        var displayList = new List<int>();
        int endVal;
        if (firstVal > secondVal)
        {
            endVal = firstVal;
            range = Enumerable.Range(secondVal, firstVal);
        }
        else
        {
            endVal = secondVal;
            range = Enumerable.Range(firstVal, secondVal);
        }

        foreach (var x in range)
            if (x <= endVal)
            {
                displayList.Add(x);
            }
        return displayList;

    }
}