Wolfram is, and has always been, much more inclined to understand you if you work out what exactly you are trying to calculate before hand.

Some phrases exist as a "wow, 1 million people phrase this problem this way, let's throw that in." The fact it can take an easily dictated, albeit strictly phrased problem, and get you your answer is really what I love about it. Now if Siri would just stop sending stuff to Google. -_-