Went to see dissapearing number last night at the Barbican. Apparently,

Srinivasa Ramanujan proved that 1+2+3+... = -1/12, I believe using the zet function?

Can anyone explain how this can be. I am high sch maths teacher, but would like to see how this is proved.

If you can help, I would really appreciate it.

Thanks

Mrt1