Drop Down Selection "Yes" to subtract from cell

[SPW]

Hi

I have an excel spreadsheet that when I select from the drop down menu "Yes" I need it to subtract 1 unit from another cell.

Example:

When the drop selection "Yes" is selected as the item has been completed.
I need to be able to subtract 1 from total amount. Both Marked in red outline

what would the formula be for this.

 

[SanjayGMusafir]

Can't do excel thing on screenshot. Please share XL2BB of your data to understand the complexity of whole scenario. There may be too much of interlinked data that may get impacted.

 

[SPW]

Can't do excel thing on screenshot. Please share XL2BB of your data to understand the complexity of whole scenario. There may be too much of interlinked data that may get impacted.

Hi Unable to Download XL2BB as it is a work computer and everything is blocked. Is there any other way of doing this.

 

[SanjayGMusafir]

Can't help in a random situation. I'm sure the figure 3 (highlighted in your screenshot) is linked to some data. It can't be a random number.

Hope someone better than me sees the thread and helps you in a best possible way.