Let's evaluate the possibilities.
First, an integer number is a whole number (not a fractional number) that can be positive, negative, or zero. So, -3, -2, ... 0, 3, 4..
-1 < a ≤ 2, means:
As we can see, a can be 0, 1 or 2.
The symbol ≤ means that a is lesser or equal to 2, while the symbol < means that 1 is lesser than a, but a is not included.
So, the answer is: "a" = 0, 1 or 2. Which can also be represented in a set S = {0, 1, 2}.
