Use of Common Content Knowledge to investigate solutions
In the discussion of the second assessment item, several of the teachers used their Common
Content Knowledge to express the need for knowing how many baseballs were in the
collection. This resulted in some teachers using their Common Content Knowledge to
determine and share their solution. For example, in Kathy’s group, after one teacher
described how she used n to represent the number of baseballs and compared two to six
multiplicatively, Kathy offered her own approach to solving the item.
I did that, but then I assumed a number– I said let’s use b and then I wrote ‘assume b
is 12’. Then I solved it for that. But I didn’t do the fractional piece – I did like ‘two
baseballs per kid’ or ‘six baseballs per kid’.
In demonstrating her knowledge of the concepts and procedures associated with this
level of the LT, this use of her Common Content Knowledge allowed Kathy to clarify the
factor-based change levels of the EPLT for herself by determining a procedure to solve a
task.