Children in grades 2 and 4 through 7 of average intelligence with (a) learn
ing disabilities (LD, n = 29) and (b) not identified as having learning dis
abilities (NLD, n = 30) were individually tested In a task that investigate
d the development of proportional structures of thought. Four of the childr
en in the LD group were not classified hut were receiving basic skills inst
ruction due to their poor performance in mathematics both on standardized t
esting and in the classroom. Mathematical knowledge was additionally assess
ed on the Woodcock-Johnson Tests of Achievement-Revised (WJTA-R). In this c
ross-sectional design, students in both groups coordinated increasingly mor
e complex relationships among the elements of the problem as a function of
grade. However, significantly fewer children with LD had constructed second
-order logical structures necessary to act on problems using multiplicative
and preproportional reasoning. No children in either group demonstrated fo
rmal proportional reasoning although a small minority evidenced qualitative
proportional reasoning. On the applied problems test of the WJTA-R, the st
udents with LD generally performed below same-aged peers, although they ach
ieved approximately at grade level on this task. For both groups, the expli
citly taught procedures to solve computation and word problems as measured
on the WJTA-R failed to accurately represent the degree of operational logi
c in children's biologically based structures of logical-mathematical activ
ity. Diagnostic and remedial implications are discussed.