Macro for Increasing/Decreasing Number (Apartment Managing)

[wahappen]

Version: MS excel 2007
Hi. I have question related to a macro that automatically changes the value in a cell depending on the number of room available in an apartment. In the first picture, the cells with a grey background fill represents the room that are available and that value is displayed on the cell with the red pen mark.

<a href="http://s1142.photobucket.com/albums/n612/jiyoon_pp/?action=view&current=1.jpg" target="_blank"><img src="http://i1142.photobucket.com/albums/n612/jiyoon_pp/1.jpg" border="0" alt="Photobucket"></a>

Now when I copy the format of a cell with a different background fill than the grey ones and apply it on an available room, the value automatically decreases by 1.

<a href="http://s1142.photobucket.com/albums/n612/jiyoon_pp/?action=view&current=2.jpg" target="_blank"><img src="http://i1142.photobucket.com/albums/n612/jiyoon_pp/2.jpg" border="0" alt="Photobucket"></a>

<a href="http://s1142.photobucket.com/albums/n612/jiyoon_pp/?action=view&current=3.jpg" target="_blank"><img src="http://i1142.photobucket.com/albums/n612/jiyoon_pp/3.jpg" border="0" alt="Photobucket"></a>
Note that if I copy the format of a grey cell and apply it on a colored cell, the value will increase by 1.

Can anyone please explain how I make this macro? Thank you for your time.

 

[AlphaFrog]

I think this would do what you want.

http://www.mrexcel.com/td0106.html

 

[wahappen]

Thank you very much. I'll read it through.