## Tuesday, March 4, 2014

Submitted without comment:

Oh, the Humanity ...

1. Yeah, at some point I guess Casio switched to a concatenation-before-multiplication scheme. This plays out with the Classpad (sorry for the blurry picture):

http://imgur.com/q8ZruWi

I respect the way the TI-89 deals with it:

http://imgur.com/14Nx8oQ

But I tend to agree with the way Wolfram does it:

http://www.wolframalpha.com/input/?i=m%2Fm%28m%29

This does remind me, though, of the way we use units in expressions. For example, we wouldn't want our students to simplify the expression 6 ft^2 and get 36 ft^2, since only the units are being squared. However, we seem ok with simplifying the expression 10 ft / 5 ft and getting an answer of 2 (as opposed to 2 ft^2). So, we seem to prefer concatenation in some situations involving units, but the rule isn't exactly clear.

What do you think?

2. I'll pick up these two images later when I get home and add them to the post ... my school blocks imgur.com as "adult". -- Curmudgeon