Update Codecademy docs.

Codecademy.md

@@ -1,11 +1,94 @@
+# Codecademy's Python 2 Course
+
+https://www.codecademy.com/courses/learn-python/lessons/python-syntax/
+
+It's gratis and accepts Python 3 syntax.
+
 # Object-oriented
 
 "The main goal of an object oriented language is to make code reusable – we do this through the use of classes and objects. If we want to design a new type of car, we can start with what they all have in common: wheels, seats, a frame. Now that we’ve determined what cars have in common, we can more easily implement any type of car we want by starting from that basic blueprint."
 
 https://discuss.codecademy.com/t/what-does-it-mean-that-python-is-an-object-oriented-language/297314
 
-# Errors
+# Errors (ex5)
 
-print("With mismatched quotes will cause a SyntaxError")
+"Mismatched quotes will cause a SyntaxError'
 
-print("Without quotes will cause a NameError")
+"SyntaxError: EOL while scanning a string literal"
+
+No quotes will cause a NameError (interprets strings as commands. )
+
+# Math (ex6)
+
+```
+mirthful_addition = 12381 + 91817
+amazing_subtraction = 981 - 312
+trippy_multiplication = 38 * 902
+happy_division = 540 / 45
+sassy_combinations = 129 * 1345 + 120 / 6 - 12
+```
+
+## Find the remainder of a number using %
+
+```
+is_this_number_odd = 15 % 2
+is_this_number_divisible_by_seven = 133 % 7
+```
+
+# Updating variables / operators.
+
+```
+sandwich_price += sales_tax
+```
+
+is the same as:
+
+```
+sandwich_price = sandwich_price + sales_tax
+```
+
+but is much shorter.
+
+## Comments
+
+Are indicated by # or """This is not for running"""
+
+# Numbers
+
+An integer is like `5`, a float is a number with a decimal point like `5.0`. They can also be in scientific notation like `2.3e7`
+
+To make sure math like `7/2` = `3.5` is correct is by inputting it into Python like `7./2.` or `float(7)/2`
+
+# Strings
+
+Multi-line strings are marked by ```"""Mulit-
+line
+strings"""```
+
+# Booleans (True/False)
+
+True = int(1)
+False = int(0)
+
+# Fun Projects
+
+Design a shop using Ex7 and Ex9 as a frame:
+
+7:
+```
+money_in_wallet = 40
+sandwich_price = 7.50
+sales_tax = .08 * sandwich_price
+
+sandwich_price += sales_tax
+money_in_wallet -= sandwich_price
+```
+
+9:
+
+```
+cucumbers = 1
+price_per_cucumber = 3.25
+total_cost = cucumbers * price_per_cucumber
+print(total_cost)
+```