Twins Bibi and Matt use the patterns on an ancient Peruvian tunic to find the Lost City of Quwi. Despite attempts at suspense, with booby traps and treacherous paths, it's a bland tale told in stilted language--clearly just a vehicle for discussing pattern types (repeating, positional, growing). Watercolor illustrations include enlarged images of the tunic's patterns--a helpful touch. Follow-up activities are appended.

This latest mathematical adventure explores patterning. Matt and Bibi are in Peru so their scientist parents can help decode the patterns on a 500-year-old tunic. All the adventure-loving twins need to hear is that the tunic belonged to the messenger of a never-discovered hidden city, and they are off and running. Riding on guanacos high in the mountains, the only thing Matt can find to keep him warm is the aforementioned tunic. Rather fortuitous, as the patterns on the tunic help them survive pitfalls along the way, while the last two patterns are the key to unlocking the city's doors. Langdo's vibrantly colored watercolors support the text, but are not enough to help readers decipher the last pattern. Focusing on repeating, positional and growing patterns, this would benefit from more examples since the story overwhelms the math. A final note provides ideas for activities to practice patterning. Similar flaws mar all the books in this series, this being no exception: lack of adult supervision, disregard for artifacts and the twins' reliance on pure luck to save the day. All in all a disappointment, although it does fill a gap in the shelf for this concept. (Picture book. 6-9)

Gr 1-4-Twins Matt and Bibi follow up Mummy Math (Holt, 2005) with a new archaeology/math adventure. This time they accompany their scientist parents to Peru. By interpreting patterns woven into an Inca shawl, the youngsters follow clues to the Lost City of Quwi, whose location has eluded explorers for centuries. While the story defies logic and teaches little about local culture, it might serve as an introduction to classroom activities on sequence and pattern perception. Langdo's cartoonlike illustrations adequately depict patterns to decipher but do little to enliven the narrative. In fact, Matt, Bibi, and their canine companion seem oddly static even in dangerous situations. A list of suggested activities follows the story's conclusion. Jennifer Rozines Roy and Gregory Roy's Patterns in Nature (Benchmark, 2005) reinforces math concepts in a more straightforward presentation.-Kathy Piehl, Minnesota State University, Mankato Copyright 2007 Reed Business Information.