November 8, 2001 Professor Adrienne G. Lavine sent the following
electronic mail message:
Two things you said helped me. The first was the hint to use
parentheses, which did start me thinking about the distributive law.
But prior to yesterday I had only thought about this briefly,
had quickly discarded the possibility of a non-tricky solution,
and had moved on to thinking of advanced uses of parentheses such as
in binomial coefficients. After failing there, I put it aside.
But yesterday when you said it used 3rd grade math, I went back to the drawing
board and thought of 24 as 6x4. In fact, here was the whole line of reasoning: