Addition Within 1000

Grade 3 · mathematics · 110 practice problems · read aloud

🔊 Listen to this explanation

Addition Within 1000

🧮 What is Addition Within 1000?

This is adding two or three-digit numbers together, where the total is less than 1000. We use this when counting large groups of items, like marbles in a jar, books in a library, or people at an event. It helps us combine amounts quickly and accurately!

📝 How to Solve: Step-by-Step

We use place value and add from right to left.

  1. Write it down: Write the numbers one on top of the other, lining up the ones, tens, and hundreds places.
  2. Add the Ones: Start with the column on the far right.
  3. Add the Tens: Move to the next column on the left.
  4. Add the Hundreds: Move to the last column on the left.
  5. Check your work!

🔍 Let's Look at Examples

Example 1: 245 + 131

  2 4 5
+ 1 3 1
  3 7 6

Steps: 5 ones + 1 one = 6 ones. 4 tens + 3 tens = 7 tens. 2 hundreds + 1 hundred = 3 hundreds. Answer: 376.

Example 2: 358 + 479 (With Regrouping!)

  1315 8
+ 4 7 9
  8 3 7

Steps:

  1. Ones: 8 + 9 = 17. Write down the 7, regroup the 1 ten to the tens column.
  2. Tens: 5 + 7 + 1 = 13. Write down the 3, regroup the 1 hundred to the hundreds column.
  3. Hundreds: 3 + 4 + 1 = 8. Write down the 8.

Answer: 837.

⚠️ Common Mistakes to Avoid

  • Misaligned Columns: If your ones, tens, and hundreds aren't lined up, you'll add the wrong places! Always check your setup.
  • Forgetting to Regroup: This is the biggest challenge! If a column adds up to 10 or more, don't forget to carry the extra digit to the next column.
  • Adding Regrouped Number Twice: Remember, the little number you carried over only gets added once in the next column.

💡 Tips & Tricks

  • Use Graph Paper: The boxes help keep your numbers in the right columns.
  • Estimate First: Round the numbers. 358 + 479 is about 360 + 480 = 840. So, your answer should be close to 840!
  • Check with Subtraction: The opposite of addition is subtraction. Check 358 + 479 = 837 by doing 837 - 479. You should get 358 back!

🎯 How to Practice

Get better by practicing a little every day!

  • Solve 5-10 problems from a workbook or worksheet.
  • Play online math games that focus on 3-digit addition.
  • Create your own problems and solve them, or quiz a friend!
  • Look for addition in real life—add up the number of pages you read in two books, or the scores in a game.

Practice problems

6 of the 110, worked through step by step — try them before opening the answer.

1 375 + 628 = ?

Hint: When adding multi-digit numbers, start from the rightmost digits and work leftward, regrouping when the sum in any column is 10 or more.

Show the answer

Answer: 1003

  1. Write the numbers one above the other, aligning the digits by place value (ones, tens, hundreds). 375 + 628
  2. Add the ones column: 5 + 8 = 13. Since 13 is 10 + 3, write down the 3 in the ones place and carry over the 1 (which is 1 ten) to the tens column. Carry: 1 375 + 628 --- 3
  3. Add the tens column: 7 + 2 = 9, plus the carried over 1 makes 10. Since 10 is 10 tens, which is 1 hundred + 0 tens, write down the 0 in the tens place and carry over the 1 (which is 1 hundred) to the hundreds column. Carry: 1 1 375 + 628 --- 03
  4. Add the hundreds column: 3 + 6 = 9, plus the carried over 1 makes 10. Since 10 hundreds is 1 thousand + 0 hundreds, write down the 0 in the hundreds place and the 1 in the thousands place. Carry: 1 1 375 + 628 ---- 1003
  5. Read the result: 1003. Final Answer: 1003

Let's add 375 and 628 step-by-step.

2 456 + 789 = ?

Hint: Start by adding the ones column first, then the tens, then the hundreds. Remember to carry over when the sum in any column is 10 or more.

Show the answer

Answer: 1245

  1. Add the ones column: 6 + 9 = 15. Write down 5 and carry over 1 to the tens column.
  2. Add the tens column: 5 + 8 + 1 (carried over) = 14. Write down 4 and carry over 1 to the hundreds column.
  3. Add the hundreds column: 4 + 7 + 1 (carried over) = 12. Write down 12.
  4. Combine all columns: 1245.

The answer is 1245.

3 567 + 289 = ?

Hint: When adding multi-digit numbers, start from the rightmost digits and work your way left, regrouping when needed. For example, when adding 48 + 37, you would add 8+7=15, write down 5 and carry over 1 to the tens place.

Show the answer

Answer: 856

  1. Add the ones place: 7 + 9 = 16. Write down 6 and carry over 1 to the tens place.
  2. Add the tens place: 6 + 8 + 1 (carried over) = 15. Write down 5 and carry over 1 to the hundreds place.
  3. Add the hundreds place: 5 + 2 + 1 (carried over) = 8.
  4. Combine all digits: 856.

The answer is 856.

4 756 + 489 = ?

Hint: When adding large numbers, start from the rightmost digits and work leftward. Remember to carry over when the sum of digits is 10 or more.

Show the answer

Answer: 1245

  1. Add the ones place: 6 + 9 = 15. Write down 5 and carry over 1 to the tens place.
  2. Add the tens place: 5 + 8 + 1 (carried over) = 14. Write down 4 and carry over 1 to the hundreds place.
  3. Add the hundreds place: 7 + 4 + 1 (carried over) = 12. Write down 12.
  4. Combine all digits: 1245.

The answer is 1245.

5 475 + 328 = ?

Hint: Look at the addition problem and think about how to add the ones, tens, and hundreds separately. Remember to regroup if the sum of any column is 10 or more.

Show the answer

Answer: 803

  1. Add the ones column: 5 + 8 = 13. Write down 3 and carry over 1 to the tens column.
  2. Add the tens column: 7 + 2 + 1 (carried over) = 10. Write down 0 and carry over 1 to the hundreds column.
  3. Add the hundreds column: 4 + 3 + 1 (carried over) = 8.
  4. Combine the results: 803.

The answer is 803.

6 375 + 428 = ?

Hint: Look at the operation symbol and think about how to add multi-digit numbers by place value

Show the answer

Answer: 803

  1. Add the ones place: 5 + 8 = 13. Write down 3 and carry over 1 to the tens place.
  2. Add the tens place: 7 + 2 + 1 (carried over) = 10. Write down 0 and carry over 1 to the hundreds place.
  3. Add the hundreds place: 3 + 4 + 1 (carried over) = 8.
  4. Combine all digits: 803.

The answer is 803.

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