Matt and Bibi unravel a pattern to discover a lost city

The Zills are visiting Peru to study the mysterious lost city of Quwi when Matt and Bibi stumble into an adventure.

With only each other, their faithful dog Riley, and an unusual ancient relic to guide them, the twins must use their understanding of patterns and sequences to locate the lost city—and the way back.

This companion to Mummy Math is a pattern-packed adventure in math that’s perfect for young readers.