Answer: The Feynman technique
Explanation:
Ellen may be suggesting Leo to use the Feynman Technique. The Feynman Technique is when someone reflects on what they learned and understand, explain it to someone else, and then review what they didn't understand or what they got wrong. For example, in this problem, Leo could learn about the formulas for the areas of shapes. Leo could fully understand and explain the formula for the area of a triangle, but struggle to understand the formula for the area of a trapezoid. Then, Leo would add that to the list of things he doesn't understand so that he can later on review the list.
Learn more about Feynman technique here: https://brainly.com/question/36680811/
Hope this helps!