It means hold down the <CTRL> key while you hit the <9> key and let it up. It hides the row or rows that cells are selected in at that time.
Obviously, it closes the current window, you are in. I'm in Grade 9 BTW Well actually i think he should try it. Be a learning experience
Yes you can. Ctrl - 9 hides a row. Ctrl - 0 hides a column. Add the Shift key to those combinations and they can be unhidden.
=4+9
Click home tab, click hide and unhide, click unhide sheet. Click home tab, click hide and unhide click hide sheet.
Ctrl - 2009 Ctrl Y 1-9 was released on: USA: 25 August 2009
The sum of 27 occurrences of the number 9 is calculated by multiplying 27 by 9, resulting in 243.
If you mean: -1/9 plus -5/9 then it is equal to -6/9 which simplifies to -2/3
2 + 5 + 9 + 12 + 16 = 44/5 = 8.8
That is 27 x 9 = 243
189
-9
263