declare a function with return value in Ruby

def add_two_numbers(a, b) 
  return a + b
end

This is a simple Ruby function that adds two numbers together. The function is named add_two_numbers, and it takes two parameters, a and b. Inside the function, the code adds the two numbers together and returns the value of the sum. The return keyword specifies the value that will be returned when the function is called. To call this function, you would need to provide two numbers as arguments, such as add_two_numbers(5, 10) which would return 15.