This study was to investigate the effects of math play activities on nurnerical progression and one to one correspondence abiliψ of children with intellectual disabilities through the multiple base비le design across children. The subjects were three children with intellectual disabilities attending edu-care center for the children with disabilities in J city. For screening of the subjects and collecting information data of the children, this study was used the social maturity scale and K-WISC-Ⅲ The study was perforrrecl thirty sessions in twice a week during the baseline phase, intervention phase, and maintenance phases. The maintenance phase was conducted four times in a week after the intervention phase. In one to one correspondence intervention, each chid performing correct responses for the presented stimulus was concomitant with a praise and a sticker as a reinforcement. And the children performing incorrect responses or no-responses were concomitant with modeling and another trial. While the corrected responses after the modeling of the researcher were concomitant with a praise only, and the incorrect responses and no-responses after modeling were concomitant with physical prompting. The results of this study were as follows; First, the math play interventions through the fishing play and math play activities crossing a stream by the stepping tones were improved numerical progression abilities of the children with intellectual disabilities. Second, the math play interventions through the fishing play and math play activities crossing a stream by the stepping stones were improved one to one correspondence abilities of the children with intellectual disabilities.