Imagine you're watching a movie, in which a character puts a chocolate bar in a box, closes the box and leaves the room. Another person, also in the room, moves the bar from a box to a desk drawer.

Most of us have little trouble working out how many milliliters are in 2.4 liters of water (it's 2,400). But the same can't ...

The system also allows people to upload their own voice snippets, which Meta says is a more scalable way to bridge the digital divide for languages that are underrepresented online.