We have the bigger projects (AC, ITE, SD) in the works, plus an FOI appeal to do, plus 2000 words for a lefty magazine due in a couple weeks. We’re kinda busy. But, we’ll try to keep the general posts ticking along. This one is some fun, plus some history and a couple of puzzles.
One of the all-time great maths scenes is Abbott and Costello’s famous bit, where Lou Costello proves that 7 x 13 = 28:
The above clip is from Abbott and Costello’s 1941 movie In the Navy, and they performed the routine a number of times. Interestingly, however, Abbott and Costello didn’t come up with the bit.
Probably, the routine is the creation of the groundbreaking vaudeville team of Flournoy Miller and Aubrey Lyles. It is typically claimed that Miller and Lyles performed the routine in the huge, 1921 all-black musical Shuffle Along, for which Miller and Lyles wrote the book and for which they contributed comedy interludes. But this is unclear, and there is reason to doubt it. Despite working hard at it, we’ve not been able to find any firm evidence that the maths bit appeared in Shuffle Along. However, Miller and Lyles definitely did the bit in the incredibly obscure 1928 short, Jimtown Speakeasy. In this version, Lyles uses “revision” and “mulsifying” and addition to prove that 3 x 17 = 24.
Many others have performed versions of the routine, including Ma and Pa Kettle in the 1951 Ma and Pa Kettle Back on the Farm, where they prove 5 x 14 = 25.
So, now the puzzles:
(1) What other equations can be proven using revision and mulsfiying?
(2) Why don’t any of the routines above include a proof by subtraction?
These clips illustrate the impact that a persuasive teacher who does not understand a subject can have on the students.
I think I’ve given others enough time so here is my answer to puzzle 1:
A 2 digit multiplicand of the form
and a single digit multiplier 
should have product 
but in these sketches has product 
.
There are a multitude of examples you could choose, although proving that
may be too much…