Hi! Excel Gurus, let say A1=2 and B1=5 then i add B1 with A1 in B1 which is = 7 i.e. B=7 (i entered this formula in B1 cell: =sum(5+A1) Now the question is: How i can keep updating the B1 cell figure (7)? for example if A1=2 and B1=7 then, when A1 is repleced with: 3 then B1=10 (i.e. 7+3) 6 then B1=16 (i.e. 10+6) 5 then B1=21 0 then B1=21 4 then B1 =25 please note that B1 should keep updating the figure of A1. And A1 figure could be any number.Also undo is must for B1 cell. Your solution will be very much appreciated.

What you are asking for is a perfect example of a Circular Reference, which is not allowed in Excel. To state your question another way, what you essentially asking is "Can I use =SUM(B1+A1) in B1." Try that and Excel will pop up the Circular Reference error message since it can't resolve a formula based on the value in the same cell as the formula. Perhaps if you explained your ultimate goal, and why you want do what you're asking, we could come up with a better solution. It may involve VBA, but I don't want to go down that path without some more details.

Thanks DerbyDad03 for your answer. one of my friend has already emailed me the macro for it which works perfectly as i need.

How did the macro handle your requirement that "undo is must for B1 cell"? Undo's are typically an issue with macros.

Derby, yes my friend told me that. you knows i have to use ' -' . say, if i entered 25 in A1 by mistake, i have to type -25 to undo it. Have a good day.