Third- through sixth-grade mathematically talented students (n = 306) enrolled in a flexibly paced mathematics course made achievement gains far beyond the normative gains expected over a one-year period. When compared to students several grade levels higher, these highly able students gained as much as 46 percentile points from pre- to posttesting. Above-grade-level testing revealed that the students possessed a wide range of mathematics knowledge prior to entering the course with some students scoring at exceptionally high levels. With an individualized learning pace, some students as young as fourth grade completed the arithmetic/prealgebra sequence in their first year and returned the second year to successfully complete the beginning algebra sequence. Restricting such students to a rigid instructional pace and a “grade-appropriate” curriculum may place them at risk for declines in motivation and achievement.