Clip 3/29: Standard 1: Making Sense and Perseverance Using Measurement Part B1
Mathematically proficient students understand and use stated assumptions, definitions, and previously established results in constructing arguments… They are able to analyze situations by breaking them into cases, and can recognize and use counterexamples.
Tracy Sola has each student create a cutout of their foot so that they can compare the size and put them in order. She asks one group to share how they would put their cutouts in order. In this case, the group lines up the heels of their footprints, so that they can compare the “heights” of the toes. She presents the students with a non-example of this strategy by arbitrarily lying down two cutouts and asking the students to compare the sizes.
A student compares the sizes of the two cutouts in Tracy’s non-example by moving them so that they are lined up at the heels.