This study examines the effects of modeling and effort attribution on children's arithmetic achievement. Children with low arithmetic achievement were divided into two instructional treatments: cognitive modeling and didactic instruction. Both treatments improved division persistence, accuracy, and perceived efficacy, but cognitive modeling led to greater accuracy gains. Effort attribution for success and difficulty had no significant effect on perceived efficacy or arithmetic performance in the context of competency development. However, the treatment combining modeling with effort attribution produced the highest congruence between efficacy judgment and performance. Self-efficacy theory posits that perceived self-efficacy influences behavior by affecting choice of activities, effort, and persistence. The study tested hypotheses from self-efficacy theory, finding that cognitive modeling was more effective than didactic instruction in promoting skill development. Modeling provided children with valid information about their arithmetic competence, which may have overridden the effects of effort attribution. Effort attribution was expected to influence self-efficacy and persistence, but it did not significantly affect the didactic treatment group. The study found that children who received modeling and effort attribution were more likely to accurately appraise their capabilities than those who received modeling alone. This may be due to the attribution helping children understand how effort affects performance. The results support the idea that children's self-perceptions of their capabilities significantly influence their subsequent achievements. The study also highlights the importance of accurate self-appraisal in predicting performance and the potential risks of misattributing failure to insufficient effort. Overall, the study underscores the role of self-efficacy in children's achievement and the importance of effective instructional methods in fostering skill development and accurate self-assessment.This study examines the effects of modeling and effort attribution on children's arithmetic achievement. Children with low arithmetic achievement were divided into two instructional treatments: cognitive modeling and didactic instruction. Both treatments improved division persistence, accuracy, and perceived efficacy, but cognitive modeling led to greater accuracy gains. Effort attribution for success and difficulty had no significant effect on perceived efficacy or arithmetic performance in the context of competency development. However, the treatment combining modeling with effort attribution produced the highest congruence between efficacy judgment and performance. Self-efficacy theory posits that perceived self-efficacy influences behavior by affecting choice of activities, effort, and persistence. The study tested hypotheses from self-efficacy theory, finding that cognitive modeling was more effective than didactic instruction in promoting skill development. Modeling provided children with valid information about their arithmetic competence, which may have overridden the effects of effort attribution. Effort attribution was expected to influence self-efficacy and persistence, but it did not significantly affect the didactic treatment group. The study found that children who received modeling and effort attribution were more likely to accurately appraise their capabilities than those who received modeling alone. This may be due to the attribution helping children understand how effort affects performance. The results support the idea that children's self-perceptions of their capabilities significantly influence their subsequent achievements. The study also highlights the importance of accurate self-appraisal in predicting performance and the potential risks of misattributing failure to insufficient effort. Overall, the study underscores the role of self-efficacy in children's achievement and the importance of effective instructional methods in fostering skill development and accurate self-assessment.