This article illustrates how teachers can use number lines to support students with or at risk for learning disabilities (LD) in mathematics. Number lines can be strategically used to help students understand relations among numbers, approach number combinations (i.e., basic facts), as well as represent and solve addition and subtraction problems.…

Validated models of mental addition processing by testing children and adults in a production task paradigm. Examined individual-difference relations between strategy choice parameters and criterion-related measures of ability. Found that individual differences in the apparently calculative processes that underlie numerical facility are highly…