Forget the number I always heard my colleagues about how much instruments in the diagram , and how long he count them . They said they spent 5 hours to count 200 instruments which was divided into 9 kinds. That's not easy , because no mistake is allowed. Sometimes I decided that I wanted to quit smoking, by means of decreasing the number of cigeratte gradually, but it's no use. Sometimes the number is boring, when things are simplied as number, that means the detail difficulty is ignored ,we only became interested with number, so it's hard to estimated the difficulty, the result can be only two : success or failuse. When the number greater than the guessed number , that means success . When the number less than the guessed number, that means failure. In such circustoms, we have a wrong method to judge the result. Sometimes , it's important to ignored the number, becoming more motivated.