Developmental Mathematics is composed of a complete workbook series progressing, level by level, through the basic elements of arithmetic into the beginnings of algebra. As a self- teaching program, Developmental Mathematics is ideal for self-paced learning, both accelerated and remedial. The student's progress is tracked and monitored periodically through Scoring and Performance modules. Its teaching methods cultivate independent thinking through deductive-reasoning and problem solving. Mathematical concepts and computational skills are presented clearly and concisely to allow students to advance independently. In each lesson, the student is taken from the lowest level of knowledge to the highest level of mastery. Developmental Mathematics can be used as both a full curriculum and a supplemental aid.
There are 20 workbooks in the series, that go from K-12 grade. Levels 1-16 cover elementary and middle school math, with 17-18 covering Algebra I and 19-20 covering beginning Geometry.
I started my son on developmental Mathematics when he was 4 and we used them exclusively for math until 3rd grade. They teach mastery of one topic at a time such as numbers, addition, subtraction etc. Very easy to follow each work book is cheap and we used volumes 1-9 in that time. I switched to Horizons at 3rd grade because there were some holes that they weren't covering like time telling and measurement. If you supplement then this is a wonderful program. My son (now 10 in pre algebra) has amazing mental math skills and I believe it is thanks to this program.