标题：RETRACTED: Comparison of students learning achievements in the subject of mathematics taught by trained teachers and untrained teachers at primary level
摘要：This article has been retracted at the request of the Author. Please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).Reason: This article was not presented at the 2010 World Conference on Educational Sciences and therefore should not have been included in this issue.
