Dona Herweck Rice 
Spectacular Sports: Flag Football [PDF ebook] 
Subtraction

Flag football is a fun sport that anyone can play. Read about flag football as you learn subtraction. This nonfiction 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 subtraction 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 math book!