Scaling Down: What Can You Do With This: Groceries

I make no secret that I really enjoy Dan Meyer's blogging and his ideas around engaging mathematics. If I was a high school Maths teacher, I'd be rewriting my own curriculum and unit plans around many of his concepts and points of challenge. But because much of his content is based around concepts that students typically engage with in that high school setting, I've been hesitant to try and scale down his ideas into my own classroom, fearing that my own mathematical knowledge would fall short and my students would flounder in the over challenging expectations.

But his recent What Can You Do With This: Groceries post was too good to resist. The simple but engaging idea - surely I could work that in during our current focus on time. The comment thread has been fun to follow and read, and the television spot made for great viewing. So, I grabbed the image from Dan's blog, threw it up on the IWB and started to see if I could scale it down to a level that would make sense to twelve and thirteen year olds. I started yesterday and continued today, but with my tandem partner, Kim, coming into the classroom tomorrow, I tried to convey the essence of what we have covered in an online chat. See if this makes sense to you.

Notes from the wiki that Kim had already read:

Numeracy - looking at the concept of speed. Start with working out the connection between time and speed and then show Dan Meyer's supermarket checkout image as a warm-up for that thinking.

What is the question that relates to speed from this image? hopefully, someone will pose the question - which checkout line is the best one to join? Which one is faster? What information do you need to know to gauge the speed of either line?

Have students dicuss how they would determine the faster line. What information would they need? What factors could stop your prediction from being true?

Graham: Maths is still investigating the grocery queue issue.
Kim: So they just go on with that too - no new instruction required?
Graham: Maths - well, they are using a set of data that the teacher Dan Meyer created but some are not sure how to proceed. You can leave it until Friday if you want.
Kim: No that's ok - have time for maths and is prob best not to start something new midway. I'll get the kids to explain the task and we'll go from there. Do I need any links?
Graham: Except I'm not 100% where it's going!! This link explains the maths task and he also appeared on CBS about his topic.
Kim: That's huge - what are the kids doing with it?
Graham: Well, we looked at the pic on the IWB, and got everyone to take an educated guess and air some theories, we then talked through what maths info was on the pic we talked about variables - credit card or cash, items that don't scan, old ladies, running out of receipt paper roll. H**** and E***** went to a supermarket and ran their own field test!!
Kim: That's cool!
Graham: Today, I threw Dan's data from his 90 minute observation and got them to talk about how they might work out which line is quicker. M**** had one method he was going to try but most were going to take a sample of ten customers, add the items scanned, add the time taken and try and work out an average of time per item that could "prove" their theory. Not perfect maths but getting them thinking and getting some of the less confident kids thinking about averages, adding time amounts so there is a bit of learning at a number of levels.
Kim: It's beaut - were they to collect this data (the items of the 10 customers?)
Graham: Yes, they have a print out of 36 customers.
Kim: OK - we'll continue on from that point. Have you had to revise averages with them at all yet?
Graham: Not as a class - can u make sense of that all?
Kim: I reckon I have now.
Graham: It's a bit messy but it was good to see more kids engaged for a change.

I should have maybe asked for help in scaling this down over on Dan's blog, but the conversation there was already very busy without me saying "Help me?" How else could we make this work well for our students? How can I ensure that good mathematics is there as well?

Print Friendly, PDF & Email

3 thoughts on “Scaling Down: What Can You Do With This: Groceries

  1. Graham Wegner

    One student was visiting the other at their house after school and they walked down to the local Foodland to buy chocolate bars. Once in the supermarket and with sugar treats in hand, they went to the checkouts where they saw two lines very similar to your image. So, in a pleasing twist that showed that this exercise got them thinking, they took a lane each to see who would get through first, testing their own hypothesis at the same time. They both even stopped to ask the cashiers how long they had been working there to establish any difference in checkout lane experience. They were pretty pleased with themselves, I can tell you.

  2. Pingback:

    Donna Benjamin (kattekrab) 's status on Sunday, 27-Sep-09 23:54:02 UTC -

Leave a Reply

Your email address will not be published. Required fields are marked *