Clip 18/41: Standard 3: Construct Arguments & Critiques Using Decimals Day 2F
Overview
Mathematically proficient students are also able to compare the effectiveness of two plausible arguments, distinguish correct logic or reasoning from that which is flawed, and—if there is a flaw in an argument—explain what it is.
As her students finish their card sorts and defend their thinking, Erika Isomura increases the rigor, inviting pairs to go beyond just solving the problem: “Make something challenging, make something that the other kids are going to be like ... then after they think about it like ‘oh yes, I got it.’ Give them a little bit of a push, okay?” She connects their thinking back to the previous lesson with fractional lengths of strings. Erika closes the lesson by praising students’ perseverance and the value of mistakes —“We like mistakes because they give us something to learn from…think of this as your prototype, this is our test run, we're trying it out, once we learn a little bit more, once we become more experts we can always go back and make some changes.” This clip also relates to standard 1 (make sense of problems and persevere in solving them).