The Fantastic Formula
Arithmetricks

Calculatrivia I (GAMES Magazine NOV/DEC 1978)
Calculatrivia II (GAMES Magazine NOV/DEC 1979)

Calculatrivia III (GAMES Magazine July/August 1981)
Calculatrivia IV (GAMES Magazine JULY 1986)

Math Problem for my Mensa Friends
Second Guessing -- Approximating

Nines Puzzle
How Much is Albuquerque?