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一个数能表示原来实际物体或事件的数量,这个数称为准确数。一个数与原来实际数相近的,这一个数称为实际数的近似数。我们在计数、度量和计算的时候,常常用近似数。一般地,如果A的近似数是a,就记作A≈a(记号“≈”表示近似相等,读作约等于)。近似数的截取方法一般有三种:1.四舍五入法这种方法是:去掉多余部分的数字后,(1)如果去掉部分的首位数字大于或等于5,就在保留部分的最后一位数上加上1;(2)如果去掉部分的首位数字小于5,保留部分不变。2.进一法这种方法是:去掉多余部分的数字后,保留部分的最后一位数上加上
A number can be said that the actual number of objects or events, this number is called the exact number. A number similar to the original actual number, this number is called the approximate number of the actual number. When we count, measure, and calculate, we often use approximations. In general, if the approximate number of A is a, it is written as A≈a (the symbol “≈” indicates approximately equal and is read as approximately equal). Approximate number of interception methods generally have three: 1. Rounding method This method is: remove the extra part of the number, (1) If the first part of the number of removed part is greater than or equal to 5, in the last part of the reserved part plus On the 1; (2) If the first part of the figure is removed less than 5, retain the same part. 2. Into a method This method is: remove the extra part of the number, the last digit of the retention part plus