A theoretical model describing young students' (Grades 1-3) functional-thinking modes was formulated and validated empirically (n = 345), hypothesizing that young students' functional-thinking modes consist of recursive patterning, covariational thinking, correspondence-particular, and correspondence-general factors. Data analysis suggested that functional-thinking tasks can be categorized on the basis of the proposed model. Analysis traced three categories of students that represent different functional-thinking profiles. Category 1 students exhibited a recursive-thinking profile. Category 2 students utilized a combination of recursive and contextual strategies and exhibited an emergent covariational and correspondence-particular thinking. Category 3 students approached functional-thinking situations flexibly, using a combination of covariational and correspondence strategies. A structural model showed two parallel paths from recursive patterning to correspondence-general through correspondence-particular or covariational.