#math trivia for #August23: Four substrings of #235 are prime: 2, 3, 5, 23. Find a three-digit number where all six substrings are prime. — Burt Kaliski Jr. (@modulomathy) August 24, 2013 Let abc be a three-digit number.  If all six substrings of abc are prime, then we must have: a, b, c are prime … Continue reading →