The hands-on RekenMathLine is an interesting cross between an abacus and a number line. Basically, various numbers of easily slid ridged rings are on a stick; one side numbered and one side plain, to quickly check your answers. Rings are always in groups of five but can be ten, twenty, or twenty-five to a line (depending on the student's skill level). The number of lines also varies: from two for beginners, to four, five, or ten for advancing students.
A variety of lessons (sold separately) have been developed for the struggling student and for the typical school scope and sequence. These might be used as a supplement to another program or (possibly) as a stand-alone program if you carefully provide enough mastery practice as well as pay attention to what skills must be mastered each year. Some free lessons and videos are available on the MathLine website (howbrite.com), but we also carry three different series. Of the companion written materials we carry, both Building Number and Understanding Operations have a delayed scope and sequence and are to be used in sequence with one another. The MathLine Concept-Building series follows a more typical scope and sequence and is aligned to state standards. ~ Janice