Sixth-grader Rufus Mayflower is betting that he can make a whole gallon of toothpaste for the same price as one tube from the store. There’s just one problem, he has to solve real-life mathematical equations first! Rufus and Kate MacKinstrey develop a simple recipe for toothpaste and manufacture, market and sell their product — all before the eighth grade! Can these two entrepreneurs keep up with the high demand for their popular product? 

Beloved children’s author Jean Merrill introduces readers to the ins and outs of a budding business, from costs to profits, in this exciting tale about perseverance, ingenuity, and underdogs.

22 Chapters – 15 Days