I said:
Or did you mean that you want to add A4 to each of the cells in B4:B12?
If that is the case, the easiest thing is usually to change whatever you
have in B4 through B12 to a formula that includes +A4. For example, if B4
is =C4-D4, change it to =C4-D4+A4.
If there is some reason why neither of those suggestions (the previous one
and the current one) works for you, explain why not. Show us what is in A4
and B4:B12. Provide some concrete examples.
PS: Of course, you could add a statement to at Worksheet_Change event
macro. But that might be "killing an ant with a sledgehammer". "Everything
should be made as simple as possible, but not simpler" --Einstein.