在上小学的时候,我对长度单位“千米”的认识非常陌生。直到工作以后,我所教的第一轮教材是人教版的小学数学教材。三年级时,我用我的小学老师的教学方法教学了“千米的认识”,但直到这时,“千米”在我面前仍像蒙上了一层薄纱,依然模糊不清,我把这之前对“千米”的认识称为第一 When I was in elementary school, I was unfamiliar with the knowledge of the length of a kilometer. After work, the first textbook I taught was a PEP math textbook. In the third grade, I taught my knowledge of the kilometer using the teaching methods of my primary school teacher, but until now, the “kilometer” still seemed to me to be covered with a thin layer of tulle, which was still unclear. I This prior knowledge of the “kilometer” as the first