reducing a number in a cell

[nerrad]

good evening
i have a spread sheet for holidays and i want to have a starting total of holidays in a cell lets say 30 days. then below this number i have made a sheet with the 12months on it with the days of the week. what i want to do is enter an X in a cell and have the number 30 reduced for every holiday booked. can this be done if so i would be truly grateful fo any replies.
i cna only assume it is some kind of formula but i have not got a clue where to start. thanks again for any replies

 

[shades]

Howdy. If I understand correctly, you could use COUNTIF

=COUNTIF(Sheet2!$A$2:$A$100,"X")

Adjust as needed

If it requires two or more conditions, use SUMPRODUCT.
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TOYOTA 1/X HISTORY

 

[nerrad]

thanks for the reply i have attached the sheet hope this help you out any as iam not sure what you meant by your formula.