1.1.1　Measurement

Measurement is to compare the measured quantity with the standard ones.Through comparison,it can be determined that the measured value is equal to several times of the measurement unit,which is combined with the multiple to show the measured value.Therefore,both the magnitudes and units of measurement value are indispensable.For example,by comparing the length of a table with that of a meter ruler,the length of the table is measured to be 1.528 meters;by comparing the weight of an iron with the counterweights,the mass of the iron block is measured to be 35.87 grams.(https://www.daowen.com)