Counting down from a fixed number

[Tom_M_1969]

In the attached document, each person has been assigned a total number of units, in Column D ("Total Units Available"). When someone types a number in Column C, it subtracts that number from the number in Column D, to show how many units are remaining. In this example, Dave started with 50 units and now has 48 left.

What I need to do is set it up so that the next time someone types a number in C6, that number is subtracted from the 48 remaining units. So, if someone were to type "10" in C6, cell E6 would count down to 38, and so on...

Is there a way to do this? Any help would be appreciated. Thanks.

[#2 · Accepted solution]

@Tom_M_1969 

I strongly recommend not doing it this way. You wouldn't have any trace of how the end result was reached, and it would be impossible to correct mistakes.

In the second sheet I have shown a way to keep track of what is used. It is easier to correct mistakes, and you still get a running total of remaining units.

[#3]

@Hans Vogelaar Thank you for the assistance! I agree that typing the updates all in one cell isn't a great idea. The problem is that units need to be calculated daily, and I was trying to avoid having 365 separate columns for them.