Abstract
In line with continuing efforts to explain the demanding nature of multiplicative reasoning among middle-school students, this study explores the fine-grained knowledge elements that two pairs of 7th and 8th graders deployed in their attempt to coordinate the known and unknown quantities in the gear-wheel problem. Failure to conceptualize the multiplicative relation in reverse, mainly due to the numeric feature of the problem parameters and inherent inverse proportional relationship, led the students to use more primitive fallback strategies.