“古人计数”(11~20各数的认识)是新世纪小学数学第四版教材一年级上册第七单元“加与减(二)”第74、75页的教学内容。本节内容是在学生逐一计数的基础上,积累十进制计数经验,建立数位概念的起始课。教材从创设富有数学文化韵味的“古人计数”的情境入手,引入对20以内数的认识。这样的编排能更好地体现自然数的产生与发展过程,丰富学 “Count the ancients ” (11 to 20 the number of understanding) is the fourth century, the textbook of the new century, the fourth edition of the seventh grade unit “plus and minus (two) ” 74,75 pages of teaching content. This section is based on student counting one by one, the accumulation of decimal counting experience, the establishment of a digital concept of the initial lesson. Teaching materials from the creation of a rich mathematical and cultural charm of the “ancients count” to start the situation, the introduction of the number of 20 or less understanding. This arrangement can better reflect the natural number generation and development process, enrich learning