I t is the number 0, which has the property that x + 0 = 0 + x = x for all rational numbers x.
There is only one set and it does have an additive identity.
Yes, it does.
Yes. The additive identity is 0.
Yes: it is 0.
Yes, it does.
Wrong! Not only is zero a real number, but it is the additive identity for the set of integers, rational numbers as well as real numbers.
Zero is the additive identity in the set of real numbers; when you add zero to any number, the number does not change its identity.
No. It has a different additive inverses for each element.
Yes.
Yes. The multiplicative identity for the rational numbers is 1 (also can be written as 1/1).
Yes, it is 1.
0 is the additive identity for the set of numbers.