coordinate
It is a representation where the distance from a reference point - the origin - represents the value of the number.
Yes, as long as the number line is entirely real.
It is any real line.
Yes.
point D
Do you mean a number line?The question you asked contains the answer. Every point on a number line corresponds to a number, and every number has a corresponding point on the number line.
coordinate
coordinate
It is the point which corresponds to 0.
A point on a number line.
The coordinate of that number.
coordinate, or coordinate value
correspondent
magnitude
Yes.
Yes.
Yes, it does.