Percents can be estimated in the same way
that other numbers can be.
 
For example, check out the large rectangle
to the right.  Can you estimate the
percentage of it that is darker?
 
       You might also try to change the part
that's dark to a certain percentage -- say to
50%.  To do that, click and hold on the dark
part and drag it upward.  Try making the
rectangle 50% dark.
 
How close have you come to 50%?  If you
click the display area on the right, the
percent of the rectangle that's covered will
be shown in the window.
 
Keep working till you get to 50% exactly.
% ?? Instruction14