How to Find Area by Subtracting Shapes

MatholiaChannel

This animated math video presents a practical geometry word problem featuring a character named Ethan who is creating a mask for a party. It guides viewers through a multi-step problem involving calculating the area of a square piece of cardboard and then subtracting the areas of cut-out shapes—specifically a rectangle for the mouth and two right-angled triangles for the eyes. The video visually demonstrates the transition from a real-world scenario to a mathematical model. The core themes explored include calculating the area of basic geometric shapes (squares, rectangles, and triangles) and the strategy of finding the area of composite figures through subtraction. It emphasizes identifying relevant dimensions from text, setting up a comprehensive equation, and performing the order of operations to solve for the final area. The visual representation clearly distinguishes between the initial material and the removed sections. For educators, this video serves as an excellent model for teaching "area of shaded region" problems or composite area. It helps students visualize why subtraction is necessary when shapes are removed, rather than added. The step-by-step solution provides a clear scaffold for setting up similar problems, making it a valuable resource for upper elementary and middle school geometry lessons focused on application and problem-solving skills.