“公倍数和公因数”是苏教版五年级下册第三单元的内容。在以前的教材中,用分解质因数的方法(短除法)求两个数的最小公倍数、最大公因数是学生必须熟练掌握的方法。但现行的新教材对这部分内容作了大胆改革,引导学生利用已有的知识和经验用列举的方法找出两个数的最小公倍数和最大公因数,而把短除 “The common multiple and the common divisor ” is the content of the third unit of the fifth edition of the Sujiao version. In the previous textbook, the factorial quality factor decomposition method (short division method) is the least common multiple of two numbers. The greatest common factor is a method that students must master. However, the current new teaching materials boldly reform this part of contents, and guide students to use the existing knowledge and experience to find the least common multiple and the greatest common factor of the two numbers by enumerating methods.