[math-fun] Kindergarten example of almost-integer mystery

A crossword puzzle with a 23x23 grid is 529/441 times as large as one with a 21x21 grid. 529/441 is almost 1.2, and the difference D satisfies 1/D = 2204.999999999853571+. Its difference from an integer satisfies |2205 - 1/D| < 1.5 e-10 --Dan Those who sleep faster get more rest.