How many blocks for a cube home?

I have not been able to post any updates in awhile do to the hustle and bustle of the school year, sickness, and an injury that affected my typing skills...

The kids were (as usual) given objectives and a set of skills that they would need.  On this day, they had to figure out how many blocks were needed to create the basic structure of their house (just the outer layer of the cube).  We discussed what it meant to develop their own strategies and some of the students already claimed to know how many blocks were needed.  I prompted them to be sure and explain to their partner HOW they came to that conclusion.

This particular problem is not a grade level skill.  It requires multiple steps and reasoning that I would consider to be advanced.  After thoroughly discussing the task and what skills were needed, I set them free.

Within about 10 minutes, I had my first group that claimed to have solved the mystery.  "144 blocks".  First I asked them to explain how they came to that conclusion.  "We multiplied."  "What did you multiply?"  "The numbers, duh."  I was a bit surprised because our regular math curriculum requires daily written explanations of how the student solved a problem.  We had discussions on a regular basis where we examined good examples and poor examples.  Clearly, we needed more work on this skill.  Group after group came with numbers that were un-reasonable.  After about half the groups had tried more than once, I decided that this was not going quite the way I planned.  I stopped everyone and we came back together.  Using our projector, I showed the class what the cube-house looked like, then showed them what just the corners looked like.

 When asked how many blocks were used to build just this portion, the kids were able to make some quick calculations and come up with much more reasonable numbers: 100, 130, 150.  Once they realized that the corners could mistakenly be counted twice, the light bulbs went off.  I had them complete the rest of the original problem.  The kids were able to see what was missing on each side of the cube-home, 6 10 by 10 walls.

 After this revelation, the kids were getting much closer to solving the problem at hand.

What did I learn from this?  That even though the motivation was there, they still struggled with a multiple step problem.  This is something that we have noticed across the curriculum with all of our students.  Once they were given some scaffolding and a starting point, they were able to make their way through.  I am a bit defeated, but we will carry on!