Partial sums express whole-number addition as a sequence of place-value-based totals: add hundreds, tens, and ones, or other convenient parts, while maintaining a running total, as in . Each intermediate total represents the quantities accumulated so far, not a separate final answer; the focus is addition within 1,000, supporting accurate written methods without extending to generalized or infinite sums.
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- Learn “Use partial sums” with a detailed explanation of the concept
- Master “Use partial sums” with unlimited, free practice problems
- Download (or modify) a free worksheet on Use partial sums you can use at home or in class with practice problems that scaffold and explore “Use partial sums” from different perspectives.
- Start working on adaptive units like “Addition and Subtraction of Integers - 1 Digit” or “Ten Groups - Adding” that introduce, teach, or practice “Use partial sums” to maximize your learning.
Detailed Explanation: Use partial sums
To use partial sums, break one number into hundreds, tens, and ones. Add each part to the running total.
Example:
Break into place-value parts:
Now add one part at a time:
- Add the hundreds:
- Add the tens to the new total:
- Add the ones to the new total:
So,
The numbers and are partial sums. They show the total so far. The final answer is .
Learn by doing: Use partial sums
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Your results
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Practice:
Addition - Whole Number 3 digit + 3 digit - Column, No Carry
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Download/Modify Free Grade 2 'Use partial sums' Worksheet
Print this free 'Use partial sums' worksheet to practice this skill away from the computer. Click 'Modify' to easily customize this worksheet to your exact needs.
This Worksheet Includes:
- Addition - Whole Number 3 digit + 3 digit - Column, No Carry
- Addition - Whole Number 2 digit + 2 digit, With Carry
- Addition - Whole Number 3 digit + 2 digit, No Carry
- Partial Sum to Equation - 3 & 3 Digit
- Partial Sum to Equation - 3 & 2 Digit
- Addition - Whole Number 2 digit + 2 digit - Column, No Carry
- Addition - Whole Number 1 digit + 1 digit, No Carry
- Addition - Whole Number 2 digit + 1 digit, No Carry
Units Teaching This Skill
These adaptive units introduce, teach, or reinforce this skill (Use partial sums) through scaffolded problems that grow in difficulty as concepts are understood.