From a biological and mathematical point of view,

People have ten fingers. When they were young, they learned to count. It is easy to count from one to ten. If they have more fingers, they must grow up to learn.

10 easy to learn and understand. Most ancient civilizations, now we use decimal every day.

Some people don't. They counted the phalanges of the other four fingers with their thumbs, each with twelve knots.

12 is easy to split. 12 can be divided into two equal parts, three equal parts, four equal parts and six equal parts to get integers, and five equal parts, eight equal parts and ten equal parts to get finite decimals. Some ancient civilizations used the decimal system, and now we also use the decimal system ("a dozen").

The least common multiple of 12 and 10 is 60 (thanks for reminding me). The trunk of China ancient 10 day is 12, which is used once every 60 cycles. 60 also has characteristics similar to 12. Some ancient civilizations adopted sexagesimal (which sounds like a big head). Now we use the units of minutes and seconds, which can be considered as sexagesimal expressed in decimal. We often divide our time equally, so it is obviously more convenient to use the divisor of 60.

From an astronomical point of view,

Find a stick and stick it in the ground. Record the length of the shadow regularly every day. The shortest day in the shadow is the summer solstice, and the longest day is the winter solstice. Coupled with the vernal equinox and autumnal equinox, which have the same time day and night, these days are about a cycle of 360 days. If you master these things, you won't miss a year's harvest, so set this time as one year. On the earth, the calendar that records time in "years" is about 360 days per year.

The moon is sometimes round and sometimes short, and it circulates every 30 days. This time is set as January. On the earth, the calendar that records time in "month" is about 30 days per month.

360/30= 12

On the earth, the calendar that records time by year, month and year is about 12 months per year.

Calendars are used to facilitate people's lives. It reflects natural phenomena and their laws. The observation results in most parts of the earth are above, so it is no coincidence that ancient civilizations used these numbers in a unified way when it was difficult to communicate. At the same time, because of the above mathematical reasons, it is not surprising that 12 has become an ordinary number (especially in divination and mythology closely related to astronomy).

This explains a lot, because in fact, a lunar month is close to 29.5 days, and a tropical year is close to 365.24 days. Counting 12.38 months a year, the earth's rotation is still changing slowly, so it is impossible to get these data accurately in ancient times, and the day of decimal calculation is beyond the reach of ordinary people.

It's just that you suddenly noticed the number 12, and then 12 "appeared many times" in your world, so you think 12 is special.

In the same way, I noticed the number 7 during this time, and then I moved my head and thought about it. "I found" seven days a week. Snow White said there were seven dwarfs and seven grunts. You can do it seven times a night, and so on

So 7 is also special?

In the final analysis, it is still limited in thinking. I hope the subject can think outside the circle.