<p>What are they, when are they used, are they important for the SAT? Thanks !</p>
<p>Use permutations when order matters.
Otherwise, go combinations</p>
<p>Not all that important for the SAT (when they do appear, the numbers are so small that it’s just as easy to list all the possibilities as it is to try to figure out the nCr/nPr entries you should make on your calculator if you’re at all unsure). But HeavenFox is right about when to use which.</p>
<p>Yeah HeavenFox is right - permutations are when order matters. (On a board of members…who is president, VP, treasurer, secretary)
Combinations are for when order doesn’t matter. (Total different combinations of members on said board)</p>