I am a bit confused to what is a rational and an integer numbers.
These following numbers are integers: $1,2,3,4,... etc.$
but these numbers are also can be written as $\frac{1}{1}, \frac{2}{1}, \frac{3}{1}, \frac{4}{1},... $ and they are called rational numbers, right?
Another example of rational numbers $1.5=\frac{3}{2}$ obviously it is not an integer.
Can integers such as $1,2,3,4,...$ are also be called a set of rational numbers?
Integers are a subset of rational numbers, meaning all integers are rational numbers, but not all rational numbers are integers.
This Venn diagram shows it best it think (ignoring the fact that there is space outside irrational and rational numbers, because the union of these two sets is the set of reals)