Three chickens laid three eggs in three days, so one chicken laid 1/3 eggs in one day.

The eggs of 9 chickens a day are 9* 1/3=3 eggs.

Number of eggs laid by 9 chickens in 9 days: 9*3=27 eggs.

Quantity is an abstract expression of the quantity of things in real life. People need some language to express the number of things (events and objects), such as the number of hunting objects, the number of sacrifices and so on.

In ancient China, this expression can be traced back to Oracle Bone Inscriptions in Shang Dynasty. In modern Chinese, some concrete forms of suffix nouns expressing quantity have been deeply preserved, such as one grain of rice, two fish, three chickens, four eggs, five horses, six cows, seven pieces of paper, eight hats, nine clothes and ten pants.

Extended data:

Quantitative relationship:

1, quantity × number of copies = total quantity

2, the total number of copies/copies = copies

3. Total number of copies = each copy

4, 1 multiple× multiple = multiple

5. How many times1time = time

6. Multiplication/Multiplication = 1 Multiplication

Baidu Encyclopedia-Quantity