Arithmetic practice · Teaching resources

3-Digit Addition

Use this worksheet to teach 3-digit addition. Work through one example with your student before assigning independent practice. The first number has 3 digits, and the second has 3 digits.

18 problemsAnswer key includedPrintable worksheetA4 & US Letter

Teaching notes for parents and teachers

Use this worksheet to teach 3-digit addition. Work through one example with your student before assigning independent practice. The first number has 3 digits, and the second has 3 digits.

How to teach it

Model lining up ones, tens, and hundreds before adding. When a column reaches ten, show the exchange for one unit in the next place. Ask your student to explain what each regrouping mark represents.

Examples to explain together

808 + 260 = 1068

Check by subtraction: 1068 − 260 = 808.

545 + 308 = 853

Check by subtraction: 853 − 308 = 545.

If your student needs help

If your student forgets a regrouped ten, match the written work to tens and ones. Check that the new ten is included once in the next column.

Check understanding

Have your student subtract one addend from the sum. Ask whether the result matches the other addend.

Make a practice set

Select the worksheet, answer key, or both. When both are selected, the answer key prints after the questions. Keep it separate if you want your student to work independently.

Print materials

After your student finishes

Review one problem together. Ask your student to explain the steps, then use the answer key to check the result. Revisit a difficult step before assigning another set.

About 3-Digit Addition

Practice 3-digit addition. Focus on accuracy before speed. Use the space provided to record the steps you need. The first number has 3 digits, and the second has 3 digits.

How to practice

Read each number by place value. Add the ones, then the tens and any remaining places. When a column totals ten or more, exchange ten units for one unit in the next place. Record the carried amount before continuing. In a horizontal problem, you may rewrite the numbers vertically; the ones must still line up.

Examples to explain together

808 + 260 = 1068

Check by subtraction: 1068 − 260 = 808.

545 + 308 = 853

Check by subtraction: 853 − 308 = 545.

If your student needs help

A carried ten belongs in the next column. Do not write a two-digit total into a single place or forget to include a carry in the next sum.

Check understanding

Subtract one addend from the sum. The result should equal the other addend.

Before independent practice

Work through one example together. Ask the student to explain one step, then try a few questions independently. Review the cause of an error before repeating the calculation. Compare the student’s written steps with the answer key where worked steps are provided; a correct answer alone does not show which strategy was used.

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