一、说教材1.教材分析。《搭积木》一课是北师大版《数学》第一册《加减法(二)》中的第二课时。这一内容是在学生已经学习了10以内数的认识、10以内数的加减法以及20以内数的认识的基础上进行的教学,是学生学习20以内加减法的第一课时,主要是要学会20以内的两位数加减一位数(不 First, teaching materials 1. Textbook analysis. “Building blocks” lesson is a second edition of the “addition and subtraction (II)” of the first volume of “Mathematics” in Beijing Normal University. This content is based on the knowledge that students have learned the number of less than 10, the number of additions and subtractions within 10 and the number of less than 20 based on the teaching, is the first class of student learning less than 20 addition and subtraction, mainly To learn to double-digit within two digits of 20 (no