My brothers and I loved this book when we were young. I think I'm going to use it as morning work or math journal warm-ups once all of my first graders are reading well enough for it. It'd be easy to use earlier in the year in second or third grade.
When I read this in Grade 4 or 5, the puzzles were challenging and engaging. Classic! Years later I still remember this book, and the other books by Jenny Tyler in this series. Loved it!