People appear to born to compute. The numerical skills of children develop so early and so inexorably that it is easy to imagine an internal clock of mathematical maturity guiding their growth. Not long after learning to walk and talk, they can set the table with impress accuracy---one knife, one spoon, one fork, for each of the five chairs.
Soon they are capable of nothing that they have placed five knives, spoons and forks on the table and, a bit later, that this amounts to fifteen pieces of silverware. Having thus mastered addition, they move on to subtraction. It seems almost reasonable to expect that if a child were secluded on a desert island at birth and retrieved seven years later, he or she could enter a second enter a second-grade mathematics class without any serious problems of intellectual adjustment.
Of course, the truth is not so simple. This century, the work of cognitive psychologists has illuminated the subtle forms of daily learning on which intellectual progress depends. Children were observed as they slowly grasped-----or, as the case might be, bumped into----- concepts that adults take for quantity is unchanged as water pours from a short glass into a tall thin one.
Psychologists have since demonstrated that young children, asked to count the pencils in a pile, readily report the number of blue or red pencils, but must be coaxed into finding the total. Such studies have suggested that the rudiments of mathematics are mastered gradually, and with effort. They have also suggested that the very concept of abstract numbers------the idea of a oneness, a twoness, a threeness that applies to any class of objects and is a prerequisite for doing anything more mathematically demanding than setting a table-----is itself far from innate
雅思分类词汇:资源环境-聚合物废物
雅思分类词汇:流体设备-图面标注
雅思分类词汇:流体设备-管道用紧固件
雅思分类词汇:流体设备-管道材料规定
雅思分类词汇:流体设备-管道布置
雅思分类词汇:流体设备-管道特殊元件
雅思词汇:留学生活常用词汇(1)
雅思分类词汇:流体设备-管道用螺纹
雅思分类词汇:流体设备-镀层及制造方法
雅思分类词汇:流体设备-填料及填料函
雅思分类词汇:流体设备-常用阀
雅思分类词汇:流体设备-弯管
雅思分类词汇:流体设备-材料统计
雅思分类词汇:资源环境-人类住区
雅思分类词汇:流体设备-其它
雅思写作必备核心词组(6)
雅思分类词汇:资源环境-能源利用
雅思分类词汇:流体设备-型材
雅思分类词汇:资源环境-环境法
雅思分类词汇:流体设备-图名
雅思分类词汇:资源环境-污染
雅思分类词汇:资源环境-采矿地质学
雅思分类词汇:资源环境-灾难
雅思分类词汇:流体设备-黑色金属
雅思分类词汇:流体设备-材料性能
雅思分类词汇:流体设备-生产用房
雅思分类词汇:流体设备-有色金属
雅思分类词汇:资源环境-污染源
雅思分类词汇:流体设备-生活用房、图名
雅思分类词汇:资源环境-运输
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |