This article is a tangible, intuitive intro to quantum mechanics – the way I wish it had been explained to me.

Probabilities can cancel

If you roll each die individually, they’ll both come up with 1’s and 2’s normally. 12% and -12% look the same when you’re not required to add them together. But if you need to add the probabilities together – as you do when one event can happen in multiple ways – then some strange stuff happens.

here’s a hack for understanding QM: if you ever hear about a weird quantum result, simply rephrase it in terms of what doesn’t happen, and then rephrase what doesn’t happen in terms of the multiple ways that it could happen adding to 0.