The purpose of this study is to understand the number and operation abilities of first grade students when entering elementary school, and to discuss the effects of pre-school education. The study was conducted on sixty-nine students in Pingtung County from elementary schools during the first four weeks of the fall semester. “TEMA-2” was adopted as the measuremen instnrument. Data were analyzed by “One-way ANOVA”. Results are as follows: (1)Most subjects performed well on numbers under ten in all aspects. (2)The first grade students in Pingtung County can already recognize two digits numbers in reading and writing in spite that the materials are not covered in the formal mathematical curriculum. (3)Different years of pre-school education experiences do not significantly affect first graders’ performances on reading and writing for two digits numbers, neither on counting, calculating, number comparisons for the one digit numbers.