1. Why did humans invent calendars? Do you think we could live

without them?

Answer: it was important to know when to plant and expect harvest or the rains or other changes in weather.

It also gave a great power to those who could say - "The Sky will be black in the middle of this particular day" - since they knew an eclipse would happen. Building became increasingly important, as did commerce, and these too required a better understanding of how Much had time passed.

People are to lazy to do simple math. We could live without them.