Rates and Pizza

My third grade class is studying unit prices this week.  They investigated in/out tables on Monday and determined how to find missing values.  During this process students started to explore strategies to solve function machines.  The class transitioned to unit prices on Wednesday.  This was more challenging, especially when students needed to find the price per ounce.  Being able to round answers and place the decimal in the appropriate place seemed to cause some issues.  Students knew what operation to use but had trouble placing the decimal.

On Friday students started off the day with a brief activator involving price per ounce.  Students were given three Starbuck cup sizes.  They had to find the price per ounce.  Students worked in groups and experimented with different strategies to find the right place to put the decimal.  The groups checked their reasonableness by multiplying their unit price answer to find the total price.  This took around 10-15 minutes.  Click here to find the template.

After this activity the class formalized a process to find the unit price of an item.  We then moved to the main project for today’s lesson.

Students were given iPads and asked to visit a pizza site.  The site was up to the student.  Students visited Papa Johns, Pizza Hut, Giordano’s, Dominos and Lou Malnati’s websites.  They were asked to customize one large pizza.  Students put together their dream pizza and found the final price.  In order to be consistent students were told that each large pizza has around nine pieces.

Students took a screen shot of their fake order and saved it to their camera roll.  They submitted their screen shots and added a caption that included a number model of the unit price.

I’m reviewing the student screenshots tonight and am finding that students are becoming better at understanding unit rates.  Next week we’ll be looking at better buy problems.