FSt1 wrote...
used in a formula, double quotes means nothing.

Ambiguous at best.

in your example formula...
if A3 is nothing(null, blank) then display the contents of A2 else display

Maybe "" == NULL, but as you use the term, null isn't the same as
#NULL! And ISBLANK("") returns FALSE.

There comes a point when failing to understand and use the program's
specific terminology becomes a problem. You've passed that point.

The most precise description of "" is zero-length string because
LEN("") == 0 and ISTEXT("") == TRUE. It's not unreasonable to call ""
an empty string. However, "" isn't "blank" in the sense that "blank"
has a particular meaning in Excel (the ISBLANK function gives its
semantics), neither is it null in the sense that "null" also has a
particular meaning in Excel (the intersection of nonoverlapping ranges,
from which the #NULL! error value arises).

the contents of A3.
if A2 and A3 are blank, then nothing will be displayed.
....

Not quite. If A3 is either blank (in the ISBLANK sense) or "", then the
OP's formula returns the value of A2. If A2 is "", then it returns "".
However, if A2 is blank (in the ISBLANK sense), then the OP's formula
returns 0 rather than "". This is one of several places where it's
important to understand the difference between blank and "".

"calline6" wrote:
then does it mean, for instance in the b.m. formula,

=if(a3="",a2,a3) whereby a3 is a name and a2 is blank
....