字母题是指用字母代替题目中的具体数字、特定符号或式子的一类题。这类题目既基于“双基”,又体现了知识的迁移,它具有类型多、涉及知识面广、抽象性强等特点,因此能很好地考查学生对“双基”知识灵活运用的能力。由于字母运算不如数字运算那样简捷直观,所以有相当一部分学生在解答此类题时有一定的困难,造成了错解率较高的情况。 在“九年义务”初中化学新教材的习题中编入了12道字母题,是旧教材习题中字母题的4倍之多。新教材从数量和内容等方面都大大地加强和丰富了字母型习题,在开发学生的智力, The letter question refers to a class of questions that use letters instead of specific numbers, specific symbols or expressions in the title. Such topics are based on the “double basis” and also embody the transfer of knowledge. They have many types, involve a wide range of knowledge, and are highly abstract. They are therefore able to examine students’ ability to use “double-base” knowledge flexibly. . Because letter operations are not as simple and intuitive as numerical calculations, a considerable number of students have certain difficulties in solving such questions, resulting in a higher rate of misinterpretation. In the exercises of the “Nine-Year Obligation” junior high school chemistry textbook, 12 letter questions were included, which is four times as many as the letters in the old textbook exercises. The new textbook has greatly enhanced and enriched the letter-type exercises in terms of quantity and content, and is developing students’ intelligence.