def add(a, b)
  puts "ADDING #{ a } + #{ b} "
  return a + b
end

def subtract(a, b)
  puts "SUBTRACTING #{ a } - #{ b }"
  return a - b
end

def multiply(a, b)
  puts "MULTIPLYING #{ a } * #{ b }"
  return a * b
end

def divide(a, b)
  puts "DIVIDING #{ a } / #{ b }"
  return a / b
end


puts "Let's do some math with just functions!"

age = add(30, 5) # 35
height = subtract(78, 4) # 74
weight = multiply(90, 2) # 180
iq = divide(100, 2) # 50

puts "Age: #{ age }, Height: #{ height }, Weight: #{ weight }, IQ: #{ iq }"

# A puzzle for the extra credit, type it in anyway
puts "Here is a puzzle."

what = add(age, subtract(height, multiply(weight, divide(iq,2))))

puts "That becomes: #{ what }. can you do it by hand?" # -4391