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### Course: 3rd grade (Eureka Math/EngageNY)>Unit 4

Lesson 4: Topic D: Applications of area using side lengths of figures

# Decomposing shapes to find area: subtract

Lindsay finds the area of an irregular shape by decomposing it into 2 rectangles and subtracting the area of the rectangles.  Created by Lindsay Spears.

## Want to join the conversation?

• why didn't you just subtract 16 from 72.
• At , she could do 72-16=56 because 72 and 16 are the results of the expressions just above. After that, she could prove, subtracting step by step. The way she followed made the calc 4x4=16 unnecessary.
• 16-72 not that hard
• It should not be hard for 3rd graders
• why does she say the area looks like a rectangle when it looks like a square?
• All squares are rectangles, but not all rectangles are squares. You can say that a square is a rectangle and be correct, but the inverse is not true, only some rectangles are squares.
• Unfortunately this is hard for some people and easy for others. Personally, it's easy for me but I completely understand why it can be hard. If you don't get it it most certainly doesn't mean you are stupid. Everyone has their tough spots. Place value is the easiest thing on earth and it took me years to understand it.
• This explains well honestly whoever made the video I say to you well done girl well done.
• her name is page
• Whenever i do a video it sometimes it doesn’t Check it off