Abstract
One of the most important items for the analyst is the handling of the numerical data. The almost analysts handle and treat the numeric data, significant figure or dispersion for example, obtained from the measurement in the correct way unconsciously. However, there are many analysts who lose the self-confidence, when they wish to use the description of the statistical terminology. This lecture is intended giving a starting point for giving the self-confidence and learning a systematic knowledge to such people. In present part of this lecture, the way of rounding of the data and the most basic part of the error will be explained.
