Clip 23/29: Day 2: Decimal Post-Lesson Debrief Part A

Mia Buljan and Erika Isomura discuss the purpose of the lesson — to let students see decimals, building off “decimal fractions” (e.g., 1/10, 1/100, and so on).



Erika wanted students to make the connection between their understanding of fractions and their emerging understandings of decimals.



Mia calls Erika’s attention to the ways in which the task challenged students in new ways, juxtaposing students’ mental predictions with calculator checks.



Regarding students’ remaining questions about decimals and patterns, Erika discusses prompting her students to make connections back to the content in their number talks. She notes that two students identified that “if I have a small number divided by a big number, I always seem to have a fraction.”



Erika also describes more general insights identified by other student pairs including one student’s identifying that the number of zeroes in the problem was related to the number of zeroes in the answer.



Mia mentions the phrase “mathematical lint,” in which small and fragile understandings gradually accrete to more substantial comprehension.