Math problem of the week, revisited

A friend of mine recently shared with me a page of his son’s 9th grade honor’s geometry homework, and it was similar this one, except that the directions were less clear.

His son got half the problems wrong because he didn’t notice that they were asking him to reflect the shape across some axis other than y and/or x.

(His son uses the Common Core-based Illustrative Math, which, like all contemporary geometry texts, provides barely any practice doing proofs).

It strikes me that yet another way that math is less about math–and more sneaky about hiding gaps in actual math skills–than it used to be is that the directions are easier to miss or (unless you’re reading carefully) to misread.

Of course, comprehending directions is an important life skill. But perhaps it should be assessed (and practiced) as a skill that’s distinct from, say, geometric transformations.

Whether transforming geometric shapes is an important life skill is another question entirely.

Extra Credit:

For which 21st century careers and college courses are 9th graders preparing for in learning to reason verbally about reflections and translations?

3 thoughts on “Math problem of the week, revisited

  1. Your extra credit question repeats the preposition “for”.

    Is this the correct counter-example? If you first translate 2 units to the right, then reflect around the x and y axes, you wind up in the wrong place.

    Would Tina’s assertion be true in a case that only allowed reflecting around axes?


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s