A part-part-whole model represents a quantity as a whole made from two parts, showing that the parts combine to make the whole and that either part can be determined when the other two quantities are known. Within 20, this structure connects addition equations with related subtraction equations and supports composing and decomposing numbers while distinguishing the total from an individual part; multi-part, larger-number, and generalized algebraic treatments are outside this scope.
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Detailed Explanation: Use a part-part-whole model
A part-part-whole model shows how two parts join to make one whole.
- The whole is the total amount.
- The parts are the smaller amounts that make the total.
Example:
There are crayons. are red. How many are blue?
First, find the whole and the known part:
- Whole: crayons
- One part: red crayons
- Missing part: blue crayons
Draw the model:
To find the missing part, subtract the known part from the whole:
So, there are blue crayons.
The model also shows the related addition fact:
The two parts, and , combine to make the whole, .
Learn by doing: Use a part-part-whole model
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Practice:
Fact Family - Addition - Triangle to Fact
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Download/Modify Free Grade 1 'Use a part-part-whole model' Worksheet
Print this free 'Use a part-part-whole model' worksheet to practice this skill away from the computer. Click 'Modify' to easily customize this worksheet to your exact needs.
This Worksheet Includes:
- Fact Family - Addition - Triangle to Fact
- Addition - Whole Number - Number Bonds to 10
- Base 10 Blocks - Adding - Number Bonds to 10
- Ten Groups - To Next Ten, One Digit, Less than 20
- Picture Numbers - Subtracting - Picture to Equation (Within 20)
- Picture Numbers - Subtracting - Picture to Equation
Units Teaching This Skill
These adaptive units introduce, teach, or reinforce this skill (Use a part-part-whole model) through scaffolded problems that grow in difficulty as concepts are understood.