弄半天，这个图片没上传好，那两张不知道怎么删

I have got the answer from the Stata.com.
We could type "help datatypes" and read the section "Precision of numeric
storage types". For additional details, we could read the Stata Blog
posting "The Penultimate Guide to Precision", written by William Gould,
StataCorp's President.
https://blog.stata.com/2012/04/0 ... guide-to-precision/   

In summary, the numeric numbers could not be precise in format float.
You could type x=float(2.6) or ,make the variable in format double to resolve the question.

1）改变存储格式Storage type, 不是显示格式display format。你现在的数据类型应该是浮点（float）或者双精度(double)，你可以改成long或者int（整数，会四舍五入丢失一部分精度）。
2）改变显示格式format