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教科书为我们提供了优质的学习素材.合理利用、有效开发这些素材,主动将教科书中的某些知识点进行拓展延伸、深度挖掘,可以开拓我们的视野,增强我们学习数学知识的兴趣.(人教版七年级数学上册教科书第45页例5)用科学记数法表示下列各数:1 000 000、57 000 000、-123 000 000 000.解:1 000 000=10~6,57 000 000=5.7×10~7,-123 000 000 000=-1.23×10~(11).思考:上面的式子中,等号左边整数的位数与右边10的指数有什么关系?用科学记数法表示一个n位整数,其中10的指数是__.观察题中的三个数据,不难发现:1000000是七位数,用科学记数法表示时10的指数为6;57 000 000是八位数,用科学记数法表示时10的指数为7;-123 000 000 000是十二位数,用科学记数法表示时10的指数为11.于是我
Textbooks provide us with high-quality learning materials, make rational use of and effectively develop these materials, and take the initiative to extend some of the knowledge in textbooks and dig deeper to broaden our horizons and enhance our interest in learning math. Example 7) The following numbers are expressed in scientific notation: 1 000 000, 57 000 000, -123 000 000 000. Solution: 1 000 000 = 10 ~ 6, 57 000 000 = 5.7 × 10 ~ 7, -123 000 000 000 = -1.23 × 10 ~ (11). Thinking: In the above formula, the number of digits to the left of the equal sign is related to the index of the right 10? The law represents an n-bit integer, of which the index of 10 is __. Three observations in the data, is not difficult to find: 1000000 is a seven-digit, scientific notation when the exponent is 6; 57 000 000 is Eight digits, expressed in scientific notation when the exponent of 10 is 7; -123,000,000,000 is a twelve-digit number that is expressed in scientific notation when the exponent of 10 is 11. So I