first, you should change:
#include <iostream.h>
to:
#include <iostream>
using namespace std;

also, this:
cout << "Press A to add the two numbers." ;
<< endl
<< "Press B to subtract the two numbers"
<< endl
<< "Press C to multiply the two numbers"
<< endl
<< "Press D to divide the two numbers"
<< endl

should read:
cout << "Press A to add the two numbers."
<< endl
<< "Press B to subtract the two numbers"
<< endl
<< "Press C to multiply the two numbers"
<< endl
<< "Press D to divide the two numbers"
<< endl;
if you'll notice, the semicolon must be added at the end of each statement, whereas you have one at the end of the first line.
You have one at the end of "Press A to add the two numbers.";
This would be correct if you then added:
cout <<
to the beginning of the following lines of code.

:-) hope that helps