A case against the x<>y key

[Thomas Radtke]

(05-10-2015 02:32 PM)hansklav Wrote:  True, but my reply was to Mark Hardman’s post, who started the whole calculation from the left side, and then a 4-level stack will not suffice.

I see (not everything-should work from left to right, too), sorry!

(05-10-2015 02:32 PM)hansklav Wrote:  The question is: which one should we teach to newbies?

The simplest not requiring doing any calculations in mind, but pointing out that algebraic considerations are unfortunately necessary: Mine .