+First, a quick word about variables. A value is an indentifier that
+are not typed. In other words, we can to any variable can hold any
+value. Most dynamic language (such as Perl, Python and Ruby) are like
+Always declare variables with a var statement, because sometimes a
+missing var can cause a hard-to-find bug. Experiments at the command
+line are the only exception to this rule.
+Strings and numbers are the simple
+We can add two strings together to produce a third string.
+There's a built-in operator called 'typeof' that returns a string
+that, sort-of, gives the type of a value.
+Because typeof is an operator (just as '+' is an operator) the
+Here we see that typeof produces (returns) a string.
+IEE 754 to represent both integers and floats.
+true and false respectively.
+Logical comparisions also produce Booleans.