The following is an excerpt from Thinking in Numbers: On Life, Love, Meaning, and Math, by Daniel Tammet, out now from Little, Brown. Ask an Icelander what comes after three and he will answer, “Three ...

Here’s a great question I got recently from a reader named David: “When it comes to numbers, I have always heard one through nine are to be spelled out and then 10 and on are to be numerals. Does a ...

Download an MP3 audio interview with the author here, or sign up for Slate’s free daily podcast on iTunes. At the other end of the scale, estimates of the number of words that an average person uses ...