What is the difference between below/above and over/under?

Question

I would like to know the difference between above and over when these words mean "more than" and the differnce between between below and under when these words mean "less than". Are some difference between them or are they interchangeable? If they are not, which ones can I fill the blank with?

1. They excluded people _____ 20 from the club.
2. Most of the events listed cost _____ £60.
3. A visa is not required for a stay of _____ three months.
4. The temperature remained _____ freezing all day.
5. The standard of his work is well _____ the average of his class.
6. Together they control just _____ 50% of the company.
7. The village is well _____ sea level.

Thanks.

Answer 1

General rule:

1. Above: It's usually used for positions. Example: The village is well above sea level.
2. Over: It's usually used for number or time. Example: a. I have been waiting for over an hour. b. I got over ten likes on this answer.

Other cases:

1. If over is used for position, it means the directly above. But above can be directly left or right above from a point or a plane.

2. If above is used, it means there is no contact(touches) between the objects. But over is generally used for two objects who touches or covers the other.

3. Over implies movement from one position/location to another. Example: The bird flew over my head. Above implies one location and no movement. Example: The bird was hovering above my head.

4. In the case of temperatures, when it will be compared with zero or the average temperature, above will be used. And for the other context, above and over both can be used. Example: a. It was six degrees above zero. b. The temperature is above 30 degrees. The temperature is over 30 degrees. (both correct)