I remember discovering the iOS calculator has a lot more features when you rotate the device into landscape orientation: <a href="http:&#x2F;&#x2F;osxdaily.com&#x2F;2011&#x2F;12&#x2F;29&#x2F;iphone-scientific-calculator&#x2F;" rel="nofollow">http:&#x2F;&#x2F;osxdaily.com&#x2F;2011&#x2F;12&#x2F;29&#x2F;iphone-scientific-calculator&#x2F;</a>  I haven&#x27;t tried recent iOS versions so I don&#x27;t know if it&#x27;s changed.  According to the comments there, everyone and their dog knew this from birth, but I think it should count as &quot;hidden&quot; functionality, and rotating to landscape is kind of like right-clicking.