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
英语四级听力长对话模拟训练第24套
英语四级听力短文理解模拟训练第3套
四级听力短文理解模拟训练第21套
四级听力复合听写模拟训练第15套
英语四级听力长对话模拟训练第6套
英语四级听力短文理解模拟训练第19套
英语四级听力长对话模拟训练第23套
英语四级听力短文理解模拟训练第7套
英语四级听力长对话模拟训练第5套
英语四级听力长对话模拟训练第3套
英语四级听力短对话模拟训练第25套
英语四级听力长对话模拟训练第25套
英语四级听力长对话模拟训练第8套
英语四级听力短文理解模拟训练第1套
英语四级听力短文理解模拟训练第2套
大学英语四六级晨读经典
英语四级听力长对话模拟训练第14套
英语四级听力长对话模拟训练第9套
英语四级听力长对话模拟训练第18套
四级听力短文理解模拟训练第22套
英语四级听力短对话模拟训练第26套
四级听力复合听写模拟训练第23套
英语四级听力短文理解模拟训练第18套
英语四级听力短文理解模拟训练第8套
英语四级听力短对话模拟训练第23套
英语四级听力短对话模拟训练第14套
英语四级听力短对话模拟训练第15套
英语四级听力短对话模拟训练第21套
英语四级听力长对话模拟训练第2套
四级听力复合听写模拟训练第3套
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |