1)IntroductionToRuby.rb

=begin
  Contents:
    Data Types: Numbers, Strings, Booleans
    Variables
    Math
    puts and print
    The .length Method
    The .reverse Method
    .upcase & .downcase
    Single-Line Comments
    Multi-Line Comments
=end

puts "### Data Types: Numbers, Strings, Booleans ###"
num = 1
puts num

boolean = true
puts boolean

string = "Ruby"
puts string

puts "### Variables ###"
number = 100
puts number

puts "### Math ###"
number1  = 2**5
puts number1

number2 = 100%3
puts number2

number3  = 2*5
puts number3

number4 = 9/3
puts number4

puts "### puts and print ###"
print "Hello "
puts "World"

puts "### The .length Method ###"
puts "My name is Alex".length

puts "### The .reverse Method ###"
string = "xelA si eman yM"
puts string
puts string.reverse

puts "### .upcase & .downcase ###"
puts "Alex".upcase
puts "Alex".downcase

puts "### Single-Line Comments ###"
# I'm a comment, bro!

puts "### Multi-Line Comments ###"
=begin
Hello!
Don't need any # symbols.
=end