Its ok if can’t wrap your head around it… the sum of 1 + 2 + 3 + 4 + 5… to infinity to me would be an exponentially huge number. Most non mathematicians would a agree, theoretically it would be right? However its wrong, the answer is in fact, -1/12 and is found all over the place in the world of Physics.
The following video does some mathematical calculations to show you how exactly that the addition of all natural numbers comes to be a negative fraction.
Even after watching the video, I am still amazed at how its possible.