Mathematica has a handy feature that will save you some typing, especially if you
tend to make typing mistakes. Suppose that we want to take the average of ten
numbers:
1+2+3+4+5+6+7+8+9+10/10
46
The answer that we get looks wrong. On close inspection, we notice that we
forgot to use parentheses around the additions. At this point we could simply
reenter the corrected question, but there's an easier way to correct our
mistake. We can actually edit the original question.
If you move the mouse cursor into the bad question and click the mouse, the
Mathematica edit cursor will appear. You can then edit the question by typing
from the keyboard. Place the cursor before the beginning of the question and
insert a left parenthesis. Then insert a right parenthesis in front of the
division symbol. Finally, type the Enter key. What happens?
Click here for the answer
The computation is performed again, the old answer is erased, and a new answer
is displayed. The Mathematica ccursor is no longer active in that cell (as you can test by typign Enter again).