Our second book in the "Crack The Safe" logic series is now complete, and available for purchase!!! In Level 2, digits might (and might not) be repeated. So, to get your logic juices flowing, here's one of the early (i.e. easier) puzzles in the book. We'll follow with a tougher one later.
If you enjoyed these (or if you need help learning to solve them) then our new book series Crack the Safe is now available. This new book contains 31 unique puzzles and includes full, detailed solutions.
Brian and Melanie Fulton both earned doctoral degrees in mathematics at Virginia Tech. They formerly taught math at the university level, and now run a hobby farm while accuracy-checking collegiate mathematics texts. They homeschool their four children, frequently employing the aid of chicken, dairy goat, cat, and dog tutors.