Try to figure out how the number b depends on the number a. To do this, move the point a over the real line (click and drag the small blue ball) and try to identify what happens with the point b! To check your answer, write in the text field below an algebraic expression in terms of a and, then, click on the button “Am I right?”. It is important that your answer matches with the point b for all positions of the point a! At the end of this page you will find the list of function commands.