321 is an integer, so the closest integer would be 321. (If 321 itself doesn't count, 322 and 320 are the same distance from it, and are the next closest.)
8 is an integer, so the answer is 8
-132
No - an integer is a whole number - the closest integers to 12.5 are 12 and 13.
The simplest fraction of 321 is 321/1, also known as the whole number 321. In terms of proper fractions (where the numerator is less than the denominator), the simplest fraction of 321 would be 321/321, which simplifies to 1/1 or just 1.
An integer is any whole number (1,2,3,-1,-2,-3, etc.). -3.12's closest integer is -3.
321 is an integer so 321
321 is an integer, not a fraction.
No - 0.8 is a decimal number, not an integer. The closest integer is 1.
8 is an integer, so the answer is 8
312 is not a sequence: it is a single 3 digit integer and one number cannot define a sequence.
It is 18 or 20
You can't write a non-integer as an integer. You can round it to the closest integer if you like, but it's not exactly the same number.
You would round it to 25.
-132
12
The closest integer larger than 4000 is 4001.
0.2 is the closest that you will get. The nearest integer, though, is 0.