ABSTRACT
The purpose of this study was to examine the effectiveness of a video modeling (VM) intervention package (including virtual manipulatives and error correction) delivered via synchronous, virtual environment to teach the mathematics skills of addition, number comparison, and subtraction to a five-year old autistic child. Using a multiple probe across skills design of a single-case experimental design, we examined whether a causal relation existed between the intervention and the child's improved accuracy of mathematics problem-solving. Following the intervention, the autistic child showed improved accuracy across all three skills and continued to solve problems with 100% accuracy during the generalization phase, which also served as the immediate maintenance phase.