There are some nice videos on youtube explaining the 1+2+3+...=-1&#x2F;12 equation.<p>For example: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=jcKRGpMiVTw" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=jcKRGpMiVTw</a>