Mental arithmetic

We were so tired last night that the television was on even though there was nothing to watch. So we watched some silly test that pitted groups purporting to be teachers, students, scientists, body-builders, blondes (any natural ones there?), construction workers, and "celebrities" against one another. The math portion consisted solely of addition of single-digit numbers, with the exception of one question, which threw a double-digit number in among the rest. There was a segment of "pick the one that doesn't belong." This involved two-dimensional line figures rotated in one plane or along one axis only. We started all this too late the hear the introduction. K. says that the constant use of calculators means that nobody he knows can do a thing without them. I know that nobody (but us) seems to bother with balancing checkbooks these days. There's shareware out there called Mental Arithmetic.