Ans_ It is Sandwich Theorem..
An infinite series contains an infinite amount if values within a set S({}. A finite series contains a certain am0unt of values (for example, the numbers from 1 to 10)
The first one is a finite set since it has a known amount of values. This can be seen as a tangible set. The second set has an unknown end. This makes it intangible.
The estimation for 279 would be 280
