Arithmetic skill and working memory in subtraction and multiplication were examined in a dual-task paradigm with phonological suppression as the interfering memory load. In dual task conditions, participants rehearsed consonant-vowel-consonant (CVCs) strings during arithmetic performance. Single task trials included a phonological suppression task only and an arithmetic performance task only. Students educated and raised in China were compared to Canadian students. Chinese students solved arithmetic problems faster than Canadian students and had fewer arithmetic errors. Of particular interest were the results from the working memory suppression task indicating little impairment on arithmetic for the Chinese and definite impairment on arithmetic for Canadians. It seems likely that non-retrieval strategies were used far more by Canadians rather than Chinese (based on arithmetic fluency scores and previous research with Chinese) and this reliance on non-retrieval strategies for Canadians may have contributed to lower arithmetic performance once a working memory load was added.