Burt Kaliski Jr. (@modulomathy) 3/18/12 8:47 PM #math trivia for #March18: #78 was a common format for what 20th century media? What other numbers were common? (NB: Not #numbertheory!) The answer to this non-number-theoretic piece of trivia is the 78-RPM record. I remember having a record player at one time with three speeds: 33, 45, … Continue reading →