Possible Answer 1:
Positive values represent elevations above sea level, while negative values are elevations below sea level. For example, a building may be +100 or simply 100 feet high. Another example: going scuba diving could lead the diver to reach a elevation of -10 meters. The value 0 is the exact location of sea level itself. In other words, if your elevation is 0, then you are at the surface of the water.
==========================================================
Possible Answer 2:
Often in money, loans and borrowing happens. If so, then we use negative numbers to indicate debt. If someone has a bank balance of say -10 dollars, then they owe the bank $10. Positive values mean that they don't owe the money and it's entirely theirs to spend however they want. A balance of 0 means they neither have money, nor do they owe anyone.
==========================================================
Possible Answer 3:
Let's say we define negative distance to mean that you walk some amount to the left (to match up with the fact the negative x values point left). So for instance, we could say the number -14 indicates you walked 14 feet to the left. Positive values on the other hand will mean you walk some amount to the right. Drawing an x axis number line is very recommended. The value 0 indicates that no walking has occurred at all.
==========================================================
Of course, when you write your answer, it should be in your words only. Those answers posted above are just a springboard to get you started.
