Dona Herweck Rice 
Tu mundo [PDF ebook] 
Germenes: Suma y resta (Your World: Germs: Addition and Subtraction)

Germs. Everybody has them! Some germs help people. Some germs can harm people. Add and subtract with tens as you learn all about germs. This Spanish math book combines math and reading skills and uses real-life examples of problem solving to teach subject-area content. The dynamic images, detailed sidebars, practice problems, and math diagrams make learning arithmetic easy and fun. Text features include a table of contents, a glossary, an index, and captions to build vocabulary and increase understanding of math and reading concepts. An in-depth problem-solving section provides additional learning and practice opportunities. Engage students with this high-interest nonfiction book!