No joke!  See this thread: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=11561336" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=11561336</a> for some real-life implementations of this technique.  Since the Fibonacci numbers are integers, at the end of your computation you&#x27;ll get a number like &quot;a + 0 sqrt(5)&quot;.  Then you can just take the &quot;a&quot; part.