Try and follow along, I dare you

This math problem will cause your brain to melt

An old Italian mathematician named Grandi created a series of math problems where all you do is ad 1 and -1s together, but you come up with different results each time. How is this possible? Watch this video to have the problem demystified!

One minus one plus one minus one - Numberphile

Wowser!

Image courtesy Flickr/Laser Burners