If I add
to my number, I get . What is my number?
Based on the number line, what was the original number?
If I start at
on a number line and end up at , what direction did I move? How many units did I move?
Experiment with the number line on the eTool below and use your observations to answer the question.
If I moved up
and then moved down , what can you tell me about my ending position?
Try making your own number line (this one should be vertical).
up and then down and see where you land.
It is the same as the starting position. Can you see why?