The lesson that I have taught before was an application of using proportions as an application for Algebra 1 and as an introduction to the lesson of similarity of polygons for Geometry. The objective of the lesson was to use ratios to find your height. First, I give my height, and the students measure my shadow with a yard, using inches as units. Then, the students measure the shadow of their partner. Then, the students use my height, my shadow, and their shadow to find out how tall are they in inches, and convert their height from inches to feet and inches. There could be errors since the Earth is moving and every minute the length of the shadow changed. This activity is to do it with plenty of sunlight. Students taller or shorter than me should get some inches larger or smaller than mine respectively. Students need to explain how they have done the procedure and compared their finding with what they know about their height. If the value that they found is not what they supposed to be, then, they need to explain the reasons for the ambiguity in their findings.

In page 37 of Van de Walle, Karp, & Bay-Williams (2013) present a table that can help every math teacher to evaluate his/her lessons (Table 3.1). I use this table to evaluate the lesson that I taught to my students. Some of the elements of the low-level cognitive of memorization task include “producing previously learned facts, rules, formulas, or definition…” and “routine, involving exact reproduction of…