发错地方了，已删除

预代数，适合小学高年级或者初中生，step-by-step，有配套习题和测试，看了一下，习题难度不高，基本概念讲的很清楚
Hardcover: 888 pages
Publisher: Pearson; 7 edition (February 6, 2014)
Language: English
ISBN-10: 0321968301
ISBN-13: 978-0321968302
Elayn Martin-Gay's developmental math program is motivated by her firm belief that every student can succeed. Martin-Gay's focus on the student shapes her clear, accessible writing, inspires her constant pedagogical innovations, and contributes to the popularity and effectiveness of her video resources. This revision of Martin-Gay's algebra series continues her focus on students and what they need to be successful.