Yes, because using a big font isn't needlessly irritating or anything.
The reason it "could" be equal to either depends on whether the (9+3) is on the numerator or denominator. If this problem were to be interpreted by a computer
[EDIT: most computers, depending on whether the programmers have made concessions precisely for this issue], then because computers follow BIDMAS pretty much accurately, what they'll see is:
48÷2×(9+3)
And because of the lack of bracket around 2×(9+3), the computer will interpret this as "take 48, divide it by 2, and then multiply what you get by 9+3", giving the answer 288. This is because, as far as a computer is concerned, "÷2" is the same as "×(1/2)" and then all the multiplications are done sequentially, so you get 48×(1/2)×(9+3).
However, because we're humans, we might think that the (9+3) lies on the denominator of the fraction, in which case what we do is "take 48, work out 2×(9+3) and then divide 48 by that", giving the answer 2. Alternatively, we might think in the same way as the computer, which is how this whole silly debate started.
Personally I think the notation is ambiguous. It's unclear whether the 9+3 should be on the numerator or denominator, and whatever the implicit prescribed rules for this sort of thing are, you could forgive anyone for making a notational error.
However these threads do illustrate why LaTeX is a good idea; far too often people don't make it clear what's on a numerator or denominator, e.g. when people write, say, 1+x/3+x, they might have meant
3+x1+x or
1+3x+x or a number of other things, and whether they got the notation right or wrong makes no difference to what they
meant. So I think future reference to this thread for such people is probably the only good thing to come out of all this.
Sigh. The maths forum is usually so nice.
EDIT: This post might also be useful for: