I would like to learn how to create a formula that takes a Value in cell A1, and on the 15th of the month subtract 25 and place the value in Cell B1. If it is not the 15th of the month, then Cell A should reflect the Amount in Cell B.

So if A1 is 1000, then on the 15th B1 will show 975 then on the 16th the value of A1 changes to 975.

I tried using this formula =IF(DAY(TODAY())=15,A1-25,B1=A1) and it worked for changing the value of A1 from 1000 to 975. But when I saved and closed the excel document, and changed the time and date on my computer to show the 16th, then reopened the spreadsheet, the Value in cell A1 remained as 1000.

And as I am writing this I have realized an added difficulty. As I am imputing the formula in, it may not be the 15th, so the information in A1 should only change after the amount has been deducted on the 15th only.