George J. Summers creates 50 new puzzles for fans eager to test their logic. The puzzles range in difficulty from the relatively simple examples at the beginning of the book to others that are tricky, complex and subtle enough to the test the expert.
Solve murder problems and robberies, see which fishermen are liars and how a blind man can identify color — purely by reasoning! Hours of mind-strengthening entertainment.
This is a collection of arithmetical puzzles which operate by substituting letters for numbers. The author clearly explains how to solve them, and they range from easy to very complex.
Challenge yourself with over 100 fresh paradoxes, puzzles, riddles, conundrums, word and number games for the jaded, skeptical puzzlist. Over 100 pages of comprehensive answers. Approximately 300 illustrations. "Excellent collection of unusual, offbeat, and completely original puzzles."—Scientific American.
More than 60 new puzzles and stunts based on the properties of numbers. Easy techniques for multiplying large numbers mentally, identifying unknown numbers, determining the date of any day in any year, interest rates worked in one’s head; such entertainments as The Lost Digit, and Psychic Bridge; over 30 pages of magic squares, triangles, cubes, much more. Inexhaustible source of stimulating mathematical recreation. 76 illustrations.
