一复习导入,引发探究1.复习引趣。师:老师在自己学校里开始上课时,总喜欢和同学们来个“头脑风暴”热热身,你们也愿意玩玩吗?(生:愿意)看大屏幕,比比哪个同学眼明脑快!(屏幕出示:6-3+2)结果是多少?(因为题简单,学生窃喜,纷纷举手,气氛热烈)师:反应果然快,你第一个举手,请说。生:6-3+2=5。师:没有意见吧?下面我就两个一起来了啊。(屏幕出示:8÷4×3,7×6+4) A review of import, trigger inquiry 1. Review interest. Teacher: the teacher started class in his school, always like and classmates to a “brainstorming ” warm-up, you are willing to play it? (The screen shows: 6-3 + 2) What is the result? (Because the questions are simple, the students are eager for joy, have raised their hands and the atmosphere is warm.) Teacher: The response is really fast. Students: 6-3 + 2 = 5. Teacher: No comment, right? Now I’m two together ah. (The screen shows: 8 ÷ 4 × 3, 7 × 6 + 4)