100! Factorial Puzzles

David Butler (@DavidKButlerUoA) of the Maths Learning Centre at the University of Adelaide runs a puzzle and games club called “One Hundred Factorial” (named after the first puzzle the club tackled – read more here).

Across the years, many of these puzzles have been shared through photos on Twitter using #100factorial. Here I aim to curate a list of all the puzzles that have been shared, with descriptions and possible solutions, eventually with some degree of organisation, to aid in finding puzzles quickly in the future.

Quarter the Cross
Colour in one quarter of this cross. You have to be sure it’s exactly one quarter. Printable Versions (From David
Read more.
Pi on the Floor
Using any of the operations of +, -, *, /, as many of the number π as you need, and
Read more.
One Hundred Factorial
The number 100! (pronounced aloud as “one hundred factorial”) is the number produced when all the numbers from 1 to
Read more.