title: Convenience methods for Ruby's Number class and 0
body: <p>I'm writing convenience methods to check if number is positive or negative like so:</p>
  
  <pre><code>class Numeric
    def positive?
      self &gt; 0
    end
  
    def negative?
      self &lt; 0
    end
  end
  </code></pre>
  
  <p>but in this case I do not know how to handle cases like these:</p>
  
  <pre><code>&gt;&gt; 0.positive?
  &gt;&gt; 0.negative?
  </code></pre>
  
  <p><strong>Update</strong>: I've updated the typo in the class name. I used numeric because I needed to check the floats as well.</p>