Saturday, September 1, 2012

Problem of the Week



A number of children are standing equally spaced around the edge of a large circle and are numbered consecutively.  Abby is 14th and Emma is 32nd and are standing directly across from each other.  How many children are there?

In a week, we will post solutions for this problem.  At that time we will also choose one commenter who gave the correct answer to get a copy of Zeroing in on Number and Operations (the commenter who wins can choose from PreK-K, 1-2, 3-4, 5-6, or 7-8).  If you want to be entered into the drawing please comment with your solution, and leave your first name last initial.

We look forward to seeing your responses!

Katie
 


 


Student Misconceptions...


I often wonder how effective we can be as teachers if we don’t first get an indication of what students misunderstand. I did a lot of work with Dynamic Classroom Assessment, George Bright and Jeane Joyner’s work and they talk about four ways to think about students’ written responses. They differentiate among “Communicating an Understanding”, “Communicating a Misunderstanding”, “Miscommunicating an Understanding”, and “Miscommunicating a Misunderstanding”. If we think about student work in terms of these categories then I believe it also means we need to have multiple representations for which we can determine whether there is understanding or not, and if it is computational or procedural, conceptual or representational.

Think about the students who submitted the following work (I am recreating it here but have not changed any of the students’ notations):

Which of the following procedures results in a larger numerical answer?

1 ½ ÷ ¾   or 1 ½ x ¾

Student A: They are the same because division is just the opposite of multiplication.
Student B: 1 ½ x ¾ because multiplication always gives a bigger answer.
Student C: They are the same because in division you just change the sign and multiply.

What was interesting is the fact that none of the students actually computed the quotient or product to allow them to check their thinking.

In talking with these students I asked them what it means to divide. None of the three students was able to articulate that division is used to determine how many equivalent groups into which a dividend can be arranged, nor given a number of groups what makes a fair share for each of the groups.

I am convinced that conceptual understanding must be developed rather than giving students “cutesy” sayings like “keep, change, flip”.  How might we, as teachers, develop a stronger conceptual model to deepen student understanding of division and then division by a fraction?  Please post your thoughts and I will be reading them and posting a follow-up to this in the next couple of weeks.

Anne