Points y and z are the same distance from point x on a number line. the coordinate of point x is –7 and the coordinate of point y is –1.
what is the coordinate of point z?

Since you know that point Y and point Z are equal distance form point F, you will need to know the distance between point Y, -1, and the distance between point X, -7. So, the total distance, after subtracting -1 from -7, is -6.  So, you will then subtract another -6 from -7, to get -13, which is the coordinate of point Z.

How many groups are there?