Beginners always want to write this:

  print "The sum of three and four is: 3+4";

And they want the 3+4 part to be evaluated, so that it prints this:

  The sum of three and four is: 7

Of course, it's a double-quoted string, so it's not evaluated.  The only
things that are evaluated in double-quoted strings are variable
references.

There are solutions to this, but most of them are ugly.  This module is
less ugly.