UnSOLVED

Looking for challenging and engaging math that extends beyond finding answers? UnSOLVED: Advanced Yet Accessible Problems in Mathematics is a series of guided explorations into problems that remain unsolved in the world of mathematics. There are no solutions; they have not been proven true or false. Each book in the series presents a different unsolved problem in an easily accessible context, yet reveals an advanced depth of understanding. Follow along to discover patterns, examine special cases, and learn about these mathematical mysteries. Mathematicians of all ages can participate in these tasks by applying elementary math concepts.

Low Floor: everyone can get on board, simple starting point
High Ceiling: room to grow and stretch beyond the start, not limiting

UnSOLVED: Graceful Trees
All trees are graceful. The problem posed in this book explores that statement. While there is a bit of graph theory vocabulary involved, only simple concepts of counting and subtracting are needed to solve these puzzles. Terms are defined, and illustrated examples guide children and adults to apply graceful labeling to tree graphs by placing odd consecutive integers into vertices. Twenty artfully designed trees from our world are presented as a backdrop for examining patterns, strategies, and combinations. What exactly is unsolved in this Graceful Tree problem?