This study evaluated the generally recommended concrete-to-abstract hierarchy for presenting a new skill, with three students with learning disabilities in grades 1, 2, and 4. The three subjects enrolled in the Multidisciplinary Diagnostic and Training Program's classroom housed on the University of Florida campus in Gainesville. Following collection of baseline data, place value concepts and skills were taught using a concrete, semiconcrete, and abstract teaching sequence in a direct instruction model. Instruction was limited to 15 minutes a day for 9 to 15 days. Student progress was monitored using Student Behavior charts, and posttest results indicated significant gains by all three subjects, with retention demonstrated 3 weeks later in a different classroom setting. Among findings were that, for all three students, the transition to abstract understanding occurred suddenly and conclusively but at varying points within the concrete-to-abstract sequence. (Contains 16 references.) (DB)