by Nick MacKinnon
Published May 21 2017 (link)
An ancient five-by-five table of letters have been found in Rome. All the ten different five-letter rows across and five-letter columns down are Roman numerals, with no letter exceeding a C. The across numbers are, in order, even, even, a cube, a prime, and a power of 2. The down numbers include a cube, the rest being even or prime.
Which two Roman numerals cross at the middle square?