Partial sums represent addition of whole numbers within 1,000 by decomposing each addend into hundreds, tens, and ones, adding corresponding place-value parts, and combining those results. This reasoning shows why regrouping may be needed when a partial sum reaches 10 or more units of a place and connects written computation to place value; it does not include general algorithms for larger numbers or algebraic summation.
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Detailed Explanation: Use partial sums
To use partial sums, break each number into hundreds, tens, and ones. Then add matching place values and combine the results.
Example: Add .
- Decompose both addends:
- Add the hundreds, tens, and ones separately:
- Combine the partial sums:
The partial sums and show regrouping because tens make hundred, and ones make ten. Therefore,
Learn by doing: Use partial sums
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Practice:
Addition - Whole Number 3 digit + 3 digit, With Carry
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Download/Modify Free Grade 3 '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, With Carry
- Addition - Whole Number 3 digit + 2 digit, With Carry
- Partial Sum to Equation - 3 & 3 Digit
- Partial Sum to Equation - 3 & 2 Digit
- Addition - Whole Number 3 digit + 2 digit, No Carry
- Addition - Whole Number 2 digit + 2 digit, With Carry
- Addition - Whole Number 2 digit + 1 digit, With Carry
- Addition - Whole Number 2 digit + 2 digit, No Carry
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