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人教版小学四年级上册数学广角有这样一道烙饼问题:“一个平底锅,每次只能烙两张饼,两面都要烙,每面烙3分钟,爸爸妈妈和我每人一张。怎样才能尽快吃上饼?”教学这个“烙饼问题”时,我事先让学生剪了几个圆纸片来代替饼,课堂上用它来模拟烙饼过程。学生通过动手操作、计算、小组讨论、交流后,主要有两种烙法:1、一张一张地烙,三次烙完,需要18分钟。2、第一次烙两张,第二次烙一张,需要12分钟。这时老师说:“还有其他的烙法吗”?没有学生回答。过了一会儿,老师又问了一遍还是没有人回答,只好由老师讲了。老师说“还有一种烙法:把三张饼标上序号分别为(1)
People PEP Primary 4 grade mathematics wide angle have such a pancake problem: ”a pan, each can only burn two cakes, both sides must be branded, each branded 3 minutes, Mom and Dad and I each one. How can I get the cake as soon as possible? “When teaching this” pancake problem “, I first asked the student to cut a few rounds of paper instead of the pie and use it to simulate the pancake process in the classroom. Students through the hands-on operation, calculation, group discussion, exchange, there are two main methods: 1, one by one to burn, three times finished ironing, you need 18 minutes. 2, the first two branded, the second one, it takes 12 minutes. Then the teacher said: ”There are other ways to burn?“? No students answer. A moment later, the teacher asked again or no one answered, but the teacher said. The teacher said ”There is also a method of branching: the three pie marked with serial numbers were (1)