Letter #1 - Dated 11/9/1922 is from Arnold Walden of Chicago, IL to a Mrs. Ruth C. Hoyt in California. The letter discusses Algebra and mathematics, among other topics.  

Letter #2 - Dated 11/29/1922 is from a Math Professor (initials ERH) at University of Missouri Columbia to Mr. Arnold Walden of Chicago, IL. The letter includes the 'article' they discussed "New Theory of Moon and Heat".

Letter #3 - Dated 12/30/1922 is from Arnold Walden to Mrs. Hoyt in which he attempts to explain how to 'square' a number.