It belongs to any set that contains it: for example, {4.75, -12, pi, sqrt(5), 29}. It belongs to the set of integers which is a proper subset of rational numbers which is a proper subset of real numbers which is a proper subset of complex numbers. So -12 belongs to all the above sets.
20 and 30, for one.
Here are some sets of numbers that have the greatest common factor of 12: 12, 36 12, 288 24, 84 24, 48, 60 60, 96 144, 156
12
The numbers are: 12 and 72
-5
It belongs to any set that contains it: for example, {4.75, -12, pi, sqrt(5), 29}. It belongs to the set of integers which is a proper subset of rational numbers which is a proper subset of real numbers which is a proper subset of complex numbers. So -12 belongs to all the above sets.
To any set that contains it! It belongs to {12}, or {12, sqrt(2), pi, -3/7}, or all whole numbers between 3 and 53, or multiples of 3, or composite numbers, or counting numbers, or integers, or rational numbers, or real numbers, or complex numbers, etc.
There are eight sets of 3 consecutive numbers in 12 hours.
-12 belongs to negative integers
belongs to an infinite number of sets. For example, the Real Numbers, the Rational Numbers, Integers, negative integers, odd negative integers, negative primes numbers, the set {12, -17, 98} or {2.76, pi, -17, k, wikianswers}. In fact any collection, however random, of numbers or other things, that includes -17.
You can select 12 numbers for the first digit, 11 numbers for the second digit, and 10 numbers for the third digit; so 12*11*10 = 1320 sets of 3 numbers can be made out of 12 different numbers.
Any set that contains -1.2, whether finite or infinite. For example, the set consisting of only -1.2 ie {-1.2}, the set consisting of -1.2 and 5 = {-1.2,5}, the set consisting of -1.2 and 3 and sqrt(17) = {-1.2,3,sqrt(17)}, and so on.
There is no single answer to that. You could come up with many sets of numbers that would have those properties.
20 and 30, for one.
It depends upon whether you use a 12 hour clock with am and pm, or a 24 hour clock. The 12 hour clock has just 1 set of 12 consecutive numbers, 1 2 3 4 5 6 7 8 9 10 11 12. The 24 hour clock has 13 sets of 12 consecutive numbers.
There are many possible sets. (1, 60) is one such.