The original version of this story appeared in Quanta Magazine. The simplest ideas in mathematics can also be the most perplexing. Take addition. It’s a straightforward operation: One of the first ...

Trading Al Horford and his massive contract to Oklahoma City is an example of addition by subtraction for Daryl Morey in his first major trade with the Sixers. Wasn’t Daryl Morey supposed to be ...

Randolph Grace receives funding from the Marsden Fund, administered by the Royal Society of New Zealand. Everyone knows that arithmetic is true: 2 + 2 = 4. But surprisingly, we don’t know why it’s ...