本册教材是根据《九年义务教育全日制数学教学大纲（试用）》和马芯兰老师的教学经验，在总结原《北京市小学数学实验教材》第一轮试教经验的基础上重新编写的。供小学三年级第二学期使用。一、本册教材的主要特点（一）加强了数的概念的教学，突出了按级计数的规律为了使学生 This textbook is based on the “nine-year compulsory education full-time mathematics syllabus (trial)” and Marcellin teacher teaching experience, based on the original “Beijing primary school mathematics experimental teaching materials,” the first round of teaching experience based on re-written. For third grade second semester use. First, the main features of the textbook (A) to strengthen the teaching of the concept of number, highlighting the law by the level of counting In order to enable students