Hopefully you don't want to do this in A2 itself because trying that will
give you a 'circular reference' error. But in another cell you can put:
=IF(A2>2000,A2+250,"not greater than 2000")
The "not greater than 2000" portion could be another formula, or reference
to a cell, such as
=IF(A2>2000,A2+250,A2)
would either show A2 + 250 or just the value in A2
=IF(A2>2000,A2+250,A3)
would show A2+250 result if A2>2000 otherwise would show value in A3
or
=IF(A2>2000,A2+250,"")
would show A2+250 result if A2>2000 otherwise would just be blank.
Hope this helps.