Mrs. Claus Pattern Problem

Mrs. Claus Pattern Problem 1, a set on Flickr. If you are working on patterning and problem solving, this is a great problem to try with your students.

This blog will now be used as a way to share my students math thinking and that of my own. I hope you enjoy the new format. I would love to keep a discussion going about student work. Please feel free to try the problem with your students. I would love to hear what yours did.

Here are some photos of how my students (Grade 2's) solved the Mrs. Claus problem.

Mrs. Claus is decorating cookies for the Elves Christmas Dinner.

She lined up the first 20 cookies and put icing on every second one.
She put a cherry on every third one.
How many cookies will have nothing on them? Show how you know.

Do some cookies have icing and a cherry? How many?
Do you see any patterns?

You write a similar problem......
The students were allowed to use any materials they wanted, paper, white boards, manipulatives, combination of any of these. The first part of the problem took us a class block. I had numbered the photos 1, 2, 3 to show you the order they were taken in as well as the progression of their thinking.

As you can see from many of the photos they were stuck on the idea of thirds. They grouped the cookies into three's giving the middle cookie the place of second each time and the last cookie the third placement with the cherry going on top.

After looking through the pictures and evaluating our discussion today, they did the problem this way to over compensate for not understanding that a cookie could have icing and a cherry on top. Many of them wanted to have a space after the cookie with the cherry on top.