《小学数学教师》2014年第2期上发表了唐彩斌老师的一篇文章《教学的艺术在于学习材料与序列的选择》。文中写到,他原先准备用一个例子:两个大小相同的硬币,周长是相等的。一枚硬币A绕着另一枚硬币B旋转一圈,硬币A转了几圈?这让我想起了美国著名的科普杂志《科学 “Primary School Mathematics Teacher” 2014 the second issue of Tang Caibin teacher’s article “The art of teaching lies in the choice of learning materials and sequences.” Written in the article, he originally prepared to use an example: two equal-sized coins, the circumference is equal. A coin around another coin B rotating circle, a few coins turn? This reminds me of the famous American science magazine "Science