"Rubix" wrote:
My question is, I want to add "if" E2 is blank
leave R2 blank in addition to formula below.
This Formula is in R2 cell.
=IF(P2<1,"A",IF(P21,"B",IF(P2<2,"G")))

It is not clear which conditions you want to give
precedence to; that is, which conditions override
the others. The following are two possibilities:

1. "E2 is blank" overrides all other conditions

=IF(E2="","",IF(P2<1,"A",IF(P21,"B",IF(P2<2,"G")) ))

2. All other conditions override "E2 is blank"

=IF(P2<1,"A",IF(P21,"B",IF(P2<2,"G",IF(E2="","")) ))

Note: I have omitted the false-value part of the last IF()
function, just as you did. In some contexts in Excel,
that is the right thing to do. But normally, I think it is
best to have a false-value part