Do you find the idea of long division amusing? Do you know what it is? This is becoming a new test of age (as opposed to a New Age test).
In 1993, I was preparing the Royal Institution Christmas lectures for BBC2. The title was "The Cosmic Onion", and the idea was that matter is akin to an onion: scientists peel away the layers in their search for the kernel of existence.
In the course of preparing my cosmic onions, I was privileged to see Ernest Rutherford's original notebooks, in which nearly 90 years ago he came up with the idea of the nuclear atom. His insight is regarded as a defining moment in human discovery.
Had I dreamed that one day I would hold Rutherford's notes, I would probably have assumed they would be bound in hardback with leather covers and gold-leaf titles. The reality was rather different: sheets of loosely clipped paper, with most of the writing in pencil.
Rutherford's writing was bold and sometimes barely legible. C for calligraphy, but A for science. At the end of the calculation that reveals the existence of what we now know as the atomic nucleus, his excitement is almost visible. The writing could barely keep pace with the insights flooding into his brain.
The critical two pages involve concepts familiar to today's sixth-formers, as well as rather simple arithmetic. People find them accessible, and they can captivate an audience. But there is one place where their age shows through - in the margin is a piece of long division.
I was taught long division in junior school. By high school we were introduced to logarithms, a powerful technique that enables numbers to be multiplied and divided by the simple addition or subtraction of their exponents. We were given "log tables", lists of the exponents corresponding to each number.
I was struck by two competing emotions. An epiphany at the sheer power of the technique was followed by panic - how would I ever manage to learn the tables? My love of science was saved by the news that we could take the tables into exams.
Later, in the sixth form, I met the slide rule, probably found only in museums today, along with the paper tapes that programmed the computers I first encountered at university in the late 1960s.
Then came the pocket calculator. Recently on TV I saw two young children being asked if four divided by three was greater or smaller than one. Both answered by punching the numbers into their calculators. I wonder if they would have realised if they had inserted the numbers in the wrong order?
The calculator has revolutionised our ability to compute. It has also killed the slide rule, the intuition of logarithms, and long division.
So now, when I give my talk and point to the margins of Rutherford's notes, I pause and say: "For the younger members of the audience, that is long division." As the years go by, it is increasingly only the adults who laugh.
Professor Frank Close is head of the particle physics group at the Rutherford Appleton Laboratory, Oxford University