Find every part of the rectangle
Multiply two two-digit factors using complete partial-product regions.
Explore this lesson →8 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- Partition one or both original factors while preserving their totals.
- Every first-factor part pairs with every second-factor part.
- The two cross regions are part of the same whole; they cannot be omitted.
- A zero part contributes no area. The calculation diagram is schematic, so use its labels rather than measuring the drawing.
- Result units follow the situation: a real length-by-width area uses square units; a count-of-items model still counts items.
Something to notice
Ask the learner to point to all part pairs, including cross regions, and explain one product's unit. Compare a count-of-labels story with a real area question. Check the final sum against the complete original rectangle.
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 4 · 4.NBT · 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.