沪教版二年级下册数学课件-2.3位值图上的游戏（11张PPT）

位值图上的游戏 5 2 3 百 十 个 ● ● ● ● ● ● ● ● ● ● 523由5个百，2个十，3个一组成 百 十 个 ● ● ● ● ● ● ● 4 2 1 421由4个百，2个十，1个一组成 用小圆片在位值图上摆出471。 百 十 个 动手摆一摆 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 471 规则：     1、每次只能加放一个小圆片。   2、记录下每次加放后的数。     3、每次加放后必须把小圆片还原，即把小圆片 送回家。 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 571 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 481 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 472 添加在百位，这个数就比原数大100 添加在十位，这个数就比原数大10 添加在个位，这个数就比原数大1 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 471 在位值图上再拿掉一块小圆片，会出现 什么情况？ 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 371 461 470 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 百位上拿走一个小圆片，这个数就比原数小100 十位上拿走一个小圆片，这个数就比原数小10 个位上拿走一个小圆片，这个数就比原数小1 在位值图上移动一片小圆片，原数将会 发生什么样的变化。 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 471 在一个三位数上，拿掉一个小圆片，根据 拿掉的位置不同，有三种不同情况出现。 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● 381 372 462 561 570 480 在一个三位数中，移动一片小圆片可能有六种情况出现。 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 百 十 个 ● ● ● ● ● ● ● ● ● ● ● ● ● 本课小结： 这节课你学到了什么？