One of the reasons she is on the team is because she can do something most of the other high level math kids can't do and that is 'head-math.' Every year when we watch the kids on T.V. it floors me that there will be a long Calculus question these kids from these magnet schools can almost do in their heads but when given a 4 function question, all 3 teams freeze. Last weeks debacle was "In which way are lemons cheaper? 3 for a dollar, .25 each or 5 for 2 dollars." Silence. This after some long question involving a cosine where the teams were buzzing in on top of each other. It was good for a chuckle as my kid was rolling on the floor going "You IIIDIOTS!! It's B!"
Mental math is a skill that not everyone can do. Myself, I'm all over percents as in "If that dress is 49.99 and I have a 10% off coupon but during the hours of 1-3 it is an additional 15% off, how much is it?" I'm so there.
Apparently most of the plain engineers could come up with the answer but none of the phd applied mathematicians could.