Learn a test.com has express review guides that are basically ebooks that you can download to use with your students. Many of these are from the 20 minutes a day series and each book has 20 lessons. For a student that has struggled in earlier math levels and is having trouble moving forward, these books are perfect for review to reinforce older skills. They download as PDFs

Junior Skill Builders: Basic Math in 15 Minutes a Day

Junior Skill Builders: Math Word Problems in 15 Minutes a Day

Express Review Guides: Basic Math & Pre-Algebra

Express Review Guides: Math Word Problems

Express Review Guides: Fractions, Percentages, & Decimal

501 Measurement and Conversion Questions

501 Quantitative Comparison Questions

Junior Skill Builders: Algebra in 15 Minutes a Day

Algebra Success in 20 Minutes a Day, 3rd Edition

501 Algebra Questions, 2nd Edition

Express Review Guides: Algebra I

Just in Time Algebra

Express Review Guides: Algebra II

Geometry Success in 20 Minutes a Day, 2nd Edition

501 Geometry Questions

Just in Time Geometry, Math Builder

GED Math

Statistics Success in 20 Minutes a Day

411 SAT Algebra & Geometry Questions

SAT Math Essentials

These math ebooks and more can be found at LearningExpressEBooks

You can also purchase these actual book titles and higher level math books from this series at amazon.com