title: Wrong number of arguments (0 for 2)
body: <p>I am currently working on a small school project (Ruby) but I am getting this error (Wrong number of arguments (0 for 2)) that makes me wanna flip a table. :(</p>
  
  <p>This is the code that I am trying to get to work:</p>
  
  <pre><code>puts "How much does the product cost?"
  price = gets.to_f.round
  
  puts "How much money will you give for it?"
  money = gets.to_f
  
  change = calculate_change(price, money)
  </code></pre>
  
  <p>I use that to get the user input, round the first to a fixnum and then the second one to a float. This is how my calculate_change method looks like:</p>
  
  <pre><code>def calculate_change(price, money)
      return money - price
  end
  </code></pre>