7 days and 8 kilometers, 1 day (8/7) kilometers. 7 days to complete 1 thing, 1 day 1/7. * * * Gender: All are averages, all are divisors, and all divisors are 7. Difference: The length of the maintenance road has the numbers 8, 8/7 and quantifier kilometers. The workload includes the number 1 or 1/7, and there is no text. No matter how long the maintenance road is, it can be regarded as one thing, which is an abstraction. Of course, there is no limit to the number of words, and it is natural to divide them into several parts. The efficiency of daily work can also be understood by comparing with the actual workload, that is, 1 day: 7 days =8/7 km: 8 km = 1: 7. The specific length and quantifiers were originally there, but they were discarded, hidden and abstracted, and perceptual knowledge was upgraded to rational knowledge, which was more general and rational.