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Math Grade 2-3 Answer Key

Adding 3-Digit Numbers with Regrouping

Practice adding hundreds, tens, and ones

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Adding 3-Digit Numbers with Regrouping

Practice adding hundreds, tens, and ones

Math - Grade 2-3

Instructions: Read each problem carefully. Add the ones, tens, and hundreds. Regroup when needed and show your work.
  1. 1

    Add 247 + 386. Show your work.

    Start in the ones place, then move left to the tens and hundreds.

    247 + 386 = 633. Regroup 13 ones as 1 ten and 3 ones, then regroup 13 tens as 1 hundred and 3 tens.
  2. 2

    Add 528 + 174. Show your work.

    528 + 174 = 702. Regroup 12 ones as 1 ten and 2 ones, then regroup 10 tens as 1 hundred and 0 tens.
  3. 3

    Add 365 + 258. Show your work.

    Remember to add the carried ten when you add the tens column.

    365 + 258 = 623. Regroup 13 ones as 1 ten and 3 ones, then regroup 12 tens as 1 hundred and 2 tens.
  4. 4

    Add 489 + 236. Show your work.

    489 + 236 = 725. Regroup 15 ones as 1 ten and 5 ones, then regroup 12 tens as 1 hundred and 2 tens.
  5. 5

    A classroom has 156 red counters and 287 blue counters. Add to find the total number of counters.

    Add the ones first: 6 ones plus 7 ones makes 13 ones.

    156 + 287 = 443. The classroom has 443 counters in all.
  6. 6

    Add 642 + 189. Show your work.

    Use regrouping in both the ones place and the tens place.

    642 + 189 = 831. Regroup 11 ones as 1 ten and 1 one, then regroup 13 tens as 1 hundred and 3 tens.
  7. 7

    Add 275 + 348. Show your work.

    275 + 348 = 623. Regroup 13 ones as 1 ten and 3 ones, then regroup 12 tens as 1 hundred and 2 tens.
  8. 8

    A library has 734 picture books and 198 chapter books. Add to find the total number of books.

    After adding the ones, add the tens plus the ten you regrouped.

    734 + 198 = 932. The library has 932 books in all.
  9. 9

    Add 416 + 329. Show your work.

    416 + 329 = 745. Regroup 15 ones as 1 ten and 5 ones, then add the tens and hundreds.
  10. 10

    Add 589 + 267. Show your work.

    Both the ones column and the tens column make numbers greater than 9.

    589 + 267 = 856. Regroup 16 ones as 1 ten and 6 ones, then regroup 15 tens as 1 hundred and 5 tens.
  11. 11

    Add 395 + 405. Show your work.

    395 + 405 = 800. Regroup 10 ones as 1 ten and 0 ones, then regroup 10 tens as 1 hundred and 0 tens.
  12. 12

    Add 268 + 345. Show your work.

    Line up the digits so the ones are under ones, tens are under tens, and hundreds are under hundreds.

    268 + 345 = 613. Regroup 13 ones as 1 ten and 3 ones, then regroup 11 tens as 1 hundred and 1 ten.
  13. 13

    Add 718 + 192. Show your work.

    718 + 192 = 910. Regroup 10 ones as 1 ten and 0 ones, then regroup 11 tens as 1 hundred and 1 ten.
  14. 14

    Find both sums, then write which sum is greater: 382 + 249 and 415 + 187.

    Solve each addition problem first, then compare the hundreds, tens, and ones.

    382 + 249 = 631, and 415 + 187 = 602. The sum 631 is greater than 602, so 382 + 249 is greater.
  15. 15

    A student added 456 + 278 and wrote 624. Find the correct sum and explain the mistake.

    456 + 278 = 734. The student likely forgot to regroup 14 ones as 1 ten and 4 ones, and also needed to regroup the tens.
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