Space for gardens and games
Find the area of rectangular surfaces in real situations and name the square unit.
Explore this lesson →8 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- A whole-number rectangle can be covered by equal unit squares with no gaps or overlaps.
- The side lengths tell how many unit squares fit across each row and how many rows fit down. Multiplication counts all the squares.
- Area uses square units. Adding two side lengths does not count all the unit squares inside.
- A cut along a grid line makes two nonoverlapping rectangles. Multiply to find each part's area, then add. This is the distributive property in a rectangle.
- Changing a side length changes the rectangle. Moving an inside cut keeps the outside rectangle and total area fixed.
Something to notice
Observe physical rectangle tiling and a learner's explanation of why side multiplication counts square units. Structured answers check exact row coverings, factor-to-side construction, part areas and named square units. Either product orientation and every legal learner-selected split are accepted. Screen drawings keep the unit size fixed, but are not actual-size rulers. Independent drawing, spontaneous explanation, retention and transfer require observation. Rectilinear decomposition and perimeter are taught separately; mappings do not imply mastery.
Try it. Change it. Explain it.
Open the lesson to use its pictures and controls. In How it works, connect the picture to the idea. In Play & discover, change the quantities and notice what stays the same. In Your turn, answer questions and use the explanation to check your reasoning.
You can ask for help, draw on the thinking pad, or listen to the question and answer options. Progress distinguishes independent work from work completed with help.
Let’s try it →Curriculum connection
Grade 3 · 3.MD · US Common Core
This lesson is mapped to these standards. A completed activity is practice evidence, not a claim of mastery. Content is checked against the linked official standards and its mathematical models are tested.