>Mathematics is not an intramural sport, and as important as being first is, how one gets to one's destination is often as important as, if not more important than, the actual target.
please help me with explaining the structure and meaning of the sentence, particularly the use of as important as for two times.
Wow. That is a monster of a sentence.
I'm not surprised you're confused. The two "as important as" actually have quite different syntax and meaning from each other.
The first one is in a concessive clause "as important as being first is", and means "even though being first is important". The pattern is
as X as Y is/are/might be
It is a parenthetical clause, and doesn't contribute to the primary meaning of the sentence.
The second one is at root a straightforward comparison: "how one gets to one's destination is ... as important as ... the actual target. The pattern is
Y is as X as Z.
However, the writer has complicated it by inserting another parenthetical phrase "if not more important than". "If not", here means "or even".
So the meaning of the whole monstrosity is something like:
even though being first is important, the way you get there is at least as important as the target itself, and perhaps more important.
