On a number line, the interval between -70 and -30 includes all the numbers that fall between these two points. This can be expressed in interval notation as:
\[ (-70, -30) \]
This means that all numbers greater than -70 and less than -30 (but not including -70 and -30 themselves) are part of this interval. If you were to visualize this on a number line, it would be represented by an open interval between the two points, with potential numbers such as -69, -50, -40, -35, etc. included.