No.2 son "Mr. Engineer" was calculating square and cube roots at 4 years old. At 9 or 10 he had memorized Pi out to 50-something places past the decimal.
Today, he has memorized his driver's lic. number, SSN, his employee number, several pin #s and his credit card numbers.
Little showoff!
Son No.3, working toward teaching high school literature and science can name all the teeth, nearly every bone in the human body, plus, all the organs, and many of the glands, arteries and nerves. I used to teach him Latin words and phrases, now he teaches me.
Showoff!