Updating code for numbers module

Author: hockeygeekgirl

numbers/README.md

@@ -0,0 +1,9 @@
+# strings
+
+Python can store and manipulate numbers. You can store integers or float (numbers with decimal places)
+
+- [numeric types](https://docs.python.org/3/library/stdtypes.html#numeric-types-int-float-complex)
+
+When naming variables follow the PEP-8 Style Guide for Python Code
+ - [PEP-8 Style Guide](https://www.python.org/dev/peps/pep-0008/#naming-conventions)
+ 

numbers/code_challenge.py

@@ -0,0 +1,6 @@
+# Ask a user to enter a number
+# Ask a user to enter a second number
+# Calculate the total of the two numbers added together
+# Print 'first number + second number = answer' 
+# For example if someone enters 4 and 6 the output should read
+# 4 + 6 = 10

numbers/code_challenge_solution.py

@@ -0,0 +1,16 @@
+# Ask a user to enter a number
+first_number = input('Enter a number: ')
+
+# Ask a user to enter a second number
+second_number = input('Enter another number: ')
+
+# Calculate the total of the two numbers added together
+answer = float(first_number) + float(second_number)
+
+# Print 'first number + second number = answer' 
+# For example if someone enters 4 and 6 the output should read
+# 4 + 6 = 10
+print(first_number + ' + ' + second_number + ' = ' + str(answer))
+
+# If you do not want the decimal places you could round the answer
+print(first_number + ' + ' + second_number + ' = ' + str(round(answer)))

numbers/combining_strings_and_numbers.py

@@ -1,4 +1,14 @@
 days_in_feb = 28
+
+# The print function can accept numbers or strings
+print(days_in_feb)
+
+# The + operator can either add two numbers or it can concatenate two strings
+# it does not know what to do when you pass it one number and one string
+# This line of code will cause an error
 print(days_in_feb + ' days in February')
-# print(str(days_in_feb) + ' days in February')
+
+# You need to convert the number to a string to display the value
+# This line of code will work
+print(str(days_in_feb) + ' days in February')
 

numbers/convert_strings_to_numbers_for_math.py

@@ -1,5 +1,11 @@
 first_num = input('Enter first number ')
 second_num = input('Enter second number ')
+# If you have a string variable containing a number
+# And you want to treat it as a number
+# You must convert it to a numeric datatype
+# int() converts a string to an integer e.g. 5, 8, 416, 506
 print(int(first_num) + int(second_num))
+
+# float() converts a string to a decimal or float number e.g. 3.14159, 89.5, 1.0
 print(float(first_num) + float(second_num))
 

numbers/doing_math.py

@@ -1,5 +1,9 @@
+# Because the variables are assigned numeric values when created
+# Python knows they are numeric variables
 first_num = 6
 second_num = 2
+
+# You can peform a variety of math operations on numeric values
 print('addition')
 print(first_num + second_num)
 print('subtraction')

numbers/numbers_treated_as_strings.py

@@ -1,3 +1,10 @@
+# Python has to guess what datatype a variable should be
+
+# since the input function returns a string, the variables it populates
+# will hold string values
 first_num = input('Enter first number ')
 second_num = input('Enter second number ')
+
+# Because first_num and second_num are string variables the + operator
+# concatenates them just like concatenating first_name and last_name
 print(first_num + second_num)

numbers/print_pi.py

@@ -1,2 +1,3 @@
+# You can use variables to store numeric values
 pi = 3.14159
 print(pi)