#CMCN14 was lights out good this year. Amongst the many things I learned new – were a ton of reminders of things that I used to think about but had let slip. One of those things was the importance of an open middle, where students have a defined beginning and ending, but how they get there is largely up to them. During Dan Meyer’s talk he challenged us to find an open middle in the routine, procedural fluency building exercises students get. Most of the great problems have it – but it is a nice tool for tipping the scale for our procedural problems towards a deeper understanding.

Here’s the typical – pretty much closed middle – version of a problem about standard form:

Find the slope, y-intercept, and x-intercept of the following equation in standard form: 3x – 4y = 20

Here’s my one up

Write the equation of a line in standard form where the both intercepts are integers, and the slope is a fraction.

We could really be here all day playing with these

Write the equation of a line in standard form where the x-intercept is a fraction, the y-intercept is 7, and the slope is a negative fraction.

We can even get at MP3

Explain why it is not possible for the slope and x-intercept of a line to be an integer, but the y-intercept a fraction.

Lastly – the Asilomar conference grounds are so amazingly beautiful. Each tree, slightly beaten from the ocean breeze, stand in stillness as perfect landmarks to perseverance. And as the sun begins to set, and that air begins to cool, and those stars begin to show – it’s hard to believe that it’s all just the backdrop to a professional development experience. It’s humbling to be there – I mean you’re walking from presentation to presentation with a program booklet offering the intellects and energies of 200 amazing educators. But you only get to pick 5… good luck with that.

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Thank you for the reminder. I used this notion this morning, the students were perplexed and loved that they nearly all made entry.

PS Sending around to colleagues today…all 14 of them!