<p>Regarding the AMC...
Perhaps if one is applying to MIT that is so, but for the vast majority of students the SAT is common currency. A stellar math score isn't "[impressive]" per se, more like necessary. Furthermore, we are discussing the SAT at present, not the AMC, so I'm not sure how your comment is relevant. </p>
<p>Maybe in an ideal, TV-free world we could all memorize our primes. But you definitely need a list of primes somewhere, whether in your head or your TI-83's.</p>