“有效数字”是表示近似数精确度的一种重要方法,在实际问题中有着广泛的应用.在有效数字的定义中突出了一个数字“0”:一个近似数,从左边第一个不是0的数字起,到精确到的数位止,所有的数字,都叫这个数的有效数字.近似数中的0,都表示数位,具有占位的作用,为什么规定有的是有效 The “significant number” is an important method of representing the accuracy of the approximate number, and has a wide range of applications in practical problems. In the definition of significant digits, a number “0” is highlighted: an approximate number, the first from the left is not 0 From the figures, to the precise number of digits, all the digits are called the valid digits of this number. The zeros in the approximate digits all represent digits, which have a placeholder effect, and why some provisions are valid