1. 
using System;
namespace Exam1
{
	public class Qestion1
	{
		public static void Main()
		{
			Console.WriteLine("Please input two intergers:");
			int a = int.Parse(Console.ReadLine());
			int b = int.Parse(Console.ReadLine());

			Console.WriteLine("a * b = {0}",a*b);
			Console.WriteLine("a / b = {0}",a/b);
			Console.WriteLine("a - b = {0}",a-b);
			Console.WriteLine("a + b = {0}",a+b);
			Console.WriteLine("a % b = {0}",a%b);
		}
	}
}
2. 
Call-by-value passes copying values. So the method won’t change the values of the variables passed in.
Call-by-reference passes copying reference which refers to the memory location. So it can change the value of the variable passed into the method.
3. 
A value type stores a variable's value in the memory location. Value types in C# include:
1)Primitive data types 
(byte, sbyte, short, ushort, int, uint,long, ulong, float,double, char,&boolean)
2)Structures & 3)Enumerations.

A reference type is known by a reference, that is, a memory location that stores the address where the object resides in memory. 

                 _________________                 _________________         _____________ 
                |                 |               |                 |       |             | 
                |A value          |               |                 |       |             |
                |(int, char, bool,|               |A memory address-|------>|             |
                | double,...      |               |                 |       |             |
                |_________________|               |_________________|       |_____________|  
       
               (a) A value type		               (b) A reference type

4. 
C# allows you to define different versions of a method in class, and the compiler will automatically select the most appropriate one based on the parameters supplied. 
public int Sum(int a, int b)
{	
	int c = a+b;
	return c;
}

public double Sum(double a, double b)
{	
	double c = a+b;
	return c;
}

5. 
	Console.WriteLine("Please input an integer:");
	int x = int.Parse(Console.ReadLine());

	int cube = x*x*x;
      
	if(cube >= 10 && cube <= 150)
	{
		Console.WriteLine("You are a winner");
	}
	else
	{
		Console.WriteLine("Sorry, you didn't win this time");
	}

6.
using System;
namespace Exam1
{
   public class Qestion6
   {
      public static void Main()
      {			
         int sum = 0;
         for(int val = 1; val <= 51; val += 2)
         {
            sum += val;
         }
         Console.WriteLine("Sum of odd numbers from 1 to 51 is {0}", sum);
      }
   }
}

7. 
int input;
do
{
   Console.WriteLine("Please input an EVEN POSITIVE integer:");
   input = int.Parse(Console.ReadLine());
}while(input%2 == 1 || input < 0);

8.
public static bool StrangeOdd(int x)
{
	int y = (x-3)*(x-2);

	bool result;

	if(y%2 == 1)			
		result = true;   //y is odd		
	else 
		result = false;  //y is even

	return result;
}