Lee Emery and Kim Tamblyn have been very busy with other volunteers at TRU to organize this conference, and we owe them all a great deal of thanks.

Lee sent an email today saying that "our banquet is shaping up nicely. There will be live music (a one man electronic band) during happy hour and belly dancers between before dessert… Also, we have an acoustic musician for our Thursday evening BBQ.

It's good to know that there will be fun times as well as serious brain work going on at our annual event.

Let's hope, for the people in the residence, that there won't be any repeats of the intruding fire alarms which disturbed sleepers at Selkirk two years ago. (But it was fun, wasn't it?)

THE "C-WORD" AND OTHER MATH OBSCENITIES

By Bob Nenninger, Delta School District

Certain shorthand words or phrases are often used in mathematics instruction to refer to important processes. Unfortunately our students often remember only the shorthand catchphrase and forget the important underlying details or concepts. Thus the short term gain of the concise catchphrase, as an aid to remembering a mathematical procedure, is often more than offset by the long term pain as many students try to apply the "rule" indiscriminately in inappropriate situations.

Three examples of such commonly misused rules or procedures (but not yet the worst case – the dreaded C-word) are as follows:

  1. "Two negatives make a positive."
  2. "Change the sign when moving a number to the other side of the equation."
  3. "Cross-multiply."

Although these are useful rules when they are applied correctly, I believe that none of these phrases should ever be uttered by any elementary or secondary math teacher, because as worded they ignore the underlying mathematical reasoning. Obviously any good teacher is going to teach for conceptual understanding first and only throw in the catchphrase as a convenient summation, especially for the weaker students, but they should be avoided entirely.

Let me quickly discuss the problems with each of these, before moving on to the dreaded C-word.

  1. "Two negatives make a positive."

    • Correct when referring to a product or quotient
      e.g. (-2) x (-3) = +6 or (-6)/(-2) = +3

      But often used incorrectly by students to evaluate sums
      e.g. (-2) + (-3) = +5.

      This one is easy to fix by simply making the context explicit.
      e.g. "Negative times negative is positive", or "The product
             of two negatives is positive."