def declares a name. Last expression is the return.

Goal

Write greet and a units total.

def greet(name)
  "Hello, #{name}"
end
puts greet("Nairobi")

def total(units, price)
  units * price
end
puts total(12, 40)

def label(city = "Nairobi")
  "#{city} kiosk"
end
puts label
puts label("Kisumu")

def add(a, b)
  return a + b
end
puts add(8, 5)