Is choosing a rational number between 2.1 and 3.9 that is even impossible?

Answer 1

There's an infinite list of rational numbers that are all between 2.1 and 3.9 .

Here are a few of them:

2.11

2.12

2.2

2.3

2.4

2.6

2.7

2.9

2.99

2.99999999999

3.0

.

.

etc.

Any number that you can completely write down on paper is rational.