I have been fortunate to work with a bunch of really great second graders as a guest teacher this year. It has been super fun to see them grow in math. They love to be challenged with big numbers, and the number zero makes them giggle. The fact that you can start any counting sequence with zero groups of anything and get zero is a hoot for them. Last week, I decided to try out some of my photos I have posted under the Math in the World tab. I logged in on the classroom computer and pulled up the blog to show the photos through the projector.
I scrolled through all of them stopping for a moment to consider the math that was there in each one. The were intrigued by the children's classroom in Nicaragua, and overwhelmed by the crowd of people at the UT game.
We stopped on the photo on the cut brownies. I love this one because many fraction problems and array problems talk about a "tray of brownies". But let's face it nobody except a chef can cut a pan of brownies straight. My photo comes from a time my daughter made brownies and of course there is a chunk out of the middle too. She probably decided to take a taste!
When I asked how many brownies were there (they are just starting to talk about multiplication), they were excited. One student said he could count by ones and would have to double check that a few times. Then a couples of kids said they could count by twos (the 3 x 5 array was not immediately obvious to most of them--), and showed me how that would work. Then another child showed how he could group them by 5's, and make a ten, then 5 more. Next someone said, count by 5's! I kept probing for more and asking the children to show how each strategy would work. By the end of the discussion, the children saw that 3 x 5 was the same as 5 x 3, and the whole array (pun intended) of strategies that could be used to solve the problem.
I think using an authentic photo like this kept the problem real and fun. The discussions were light, and kids felt free to offer all kinds of ideas. I am not sure how this would work for fractions though, since the pieces are not cut evenly.
