using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var batches = Batchify( 453, 200);

        Console.WriteLine(batches.Count);

        foreach( Batch batch in batches )

        {

            Console.WriteLine("{0}-{1}", batch.Start, batch.End);

        }

    }

    public static List<Batch> Batchify( int number, int size)

    {

        List<Batch> result = new List<Batch>();

        int running = number;

        int startIndex = 0;

        do

        {

            int endIndex = running < size ? startIndex+running : startIndex+size-1;

            result.Add(new Batch{ Start = startIndex, End = endIndex });

            startIndex = endIndex+1;

            running -= size;

        }while(running > 0);

        return result;

    }

}

​

public class Batch

{

    public int Start{get;set;}

    public int End{get;set;}

}