Excel Formulas

Lately, I've noticed that in Excel, my formulas don't continue to add or do the other formula functions.  Any idea why?

 

In the past, if I put a one in a column, it would automatically add it.  The formulas are all set up as such.  For some reason, it isn't calculating and after a add more data, I have to re-install the same formula.  

 

Also, I used to format the first line for the formula then copy and paste the formula and it figured out that I am adding the second line, etc.  It doesn't do any of that now.  I'm also finding this occurring in other spreadsheets all of the sudden.

 

Did Excel change or is there a setting that might inadvertently do this?