I want to produce the time difference between the date of an entry and the first date in the date column.
I know the way to do it ... =(a16-a1)/30 will give me the number of months between the 1st and, in this example, the 16th entry, (to whatever number of decimal points I set). My question is, how do I make a1 stay constant as new entries are added down the column? For example a16-a1 will become in the next row a17-a2 unless a1 is somehow pegged to stay a1.









