Addition Within 1000

Grade 2 · mathematics · 15 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 15, worked through step by step — try them before opening the answer.

1 345 + 278 = ?

Hint: Add the ones place first, then the tens place, then the hundreds place. Remember to regroup if needed.

Show the answer

Answer: 623

  1. Write the numbers vertically, aligning the digits by place value (ones, tens, hundreds). 345 + 278
  2. Add the ones column: 5 + 8 = 13. Since 13 is 10 + 3, we write down the 3 in the ones place and carry over the 1 (which is 1 ten) to the tens column. (carry) 1 345 + 278 --- 3
  3. Add the tens column, including the carry: 1 (carry) + 4 + 7 = 12. Since 12 is 10 + 2, we write down the 2 in the tens place and carry over the 1 (which is 1 hundred) to the hundreds column. (carry) 1 345 + 278 --- 23
  4. Add the hundreds column, including the carry: 1 (carry) + 3 + 2 = 6. Write down the 6 in the hundreds place. 345 + 278 --- 623
  5. Final check — 345 + 278 = 623. ANSWER: 623

Let's add 345 and 278 step by step.

2 245 + 378 = ?

Hint: Add the ones place first, then the tens place, then the hundreds place. Remember to regroup if needed.

Show the answer

Answer: 623

  1. Write the numbers one above the other, aligning the digits by place value (units, tens, hundreds). 245 + 378
  2. Add the units column (rightmost column): 5 + 8 = 13. 13 is 3 units and 1 ten. Write down the 3 in the units place and carry over the 1 ten to the tens column. Carry: 1 245 + 378 --- 3
  3. Add the tens column: 4 + 7 = 11, plus the carried over 1 makes 12. 12 tens is 2 tens and 1 hundred. Write down the 2 in the tens place and carry over the 1 hundred to the hundreds column. Carry: 1 245 + 378 --- 23
  4. Add the hundreds column: 2 + 3 = 5, plus the carried over 1 makes 6. Write down the 6 in the hundreds place. 245 + 378 --- 623 Final answer: 623

Let's add 245 and 378 step by step.

3 245 + 367 = ?

Hint: Add the ones place first, then the tens place, and finally the hundreds place. Remember to regroup if needed.

Show the answer

Answer: 612

  1. Write the numbers one above the other, aligning the digits by place value (ones, tens, hundreds). 245 + 367
  2. Add the digits in the ones column (rightmost column). 5 + 7 = 12 Since 12 is 10 + 2, we write down the 2 in the ones place of the answer and carry over the 1 (which is 1 ten) to the tens column. Answer so far: ___2 Carry: 1
  3. Add the digits in the tens column, including the carry. The tens column has 4, 6, and the carried 1. 4 + 6 + 1 = 11 Since 11 is 10 + 1, we write down the 1 in the tens place of the answer and carry over the 1 (which is 1 hundred) to the hundreds column. Answer so far: __12 Carry: 1
  4. Add the digits in the hundreds column, including the carry. The hundreds column has 2, 3, and the carried 1. 2 + 3 + 1 = 6 Write down the 6 in the hundreds place. Answer so far: 612
  5. Combine the digits from all columns. The hundreds digit is 6, the tens digit is 1, and the ones digit is 2. So the final answer is 612. Therefore, 245 + 367 = 612.

Let's add 245 and 367 step-by-step.

4 A farmer has 345 apples in her orchard. She picks 128 more apples. How many apples does she have now?

Hint: Think about adding the two numbers together. Start by adding the ones place, then the tens place, and then the hundreds place.

Show the answer

Answer: 473

  1. Write the numbers aligned for addition: 345 + 128
  2. Add the ones place: 5 + 8 = 13 Write down 3 in the ones place, carry over 1 to the tens place.
  3. Add the tens place: 4 + 2 = 6, plus the carried over 1 makes 7. Write down 7 in the tens place.
  4. Add the hundreds place: 3 + 1 = 4. Write down 4 in the hundreds place.
  5. Combine the digits: Hundreds: 4, Tens: 7, Ones: 3 → 473. So, 345 + 128 = 473. The farmer now has 473 apples.

Let's solve this step by step. We start with the number of apples the farmer has: 345 She picks 128 more apples, so we need to add 128 to 345.

5 A rectangular garden has 8 rows of flowers. Each row has 7 flowers. How many flowers are there in the garden?

Hint: Think about how you can count equal groups. For example, if you had 3 rows with 4 trees in each, you could add 4 + 4 + 4.

Show the answer

Answer: 56

  1. Understand what is being asked. We need the total number of flowers. If each row has the same number of flowers, we can multiply the number of rows by the number of flowers in each row.
  2. Write the multiplication. Number of rows = 8 Flowers per row = 7 Total flowers = 8 × 7
  3. Perform the multiplication. 8 × 7 = 56
  4. State the final answer. There are 56 flowers in the garden.

We are told that the garden has 8 rows of flowers, and each row has 7 flowers.

6 A rectangular garden has a length of 25 meters and a width of 18 meters. What is the total distance around the garden?

Hint: Think about adding up all the sides of a rectangle. Remember that opposite sides are equal in length.

Show the answer

Answer: 86

  1. Identify the given values. Length = 25 meters Width = 18 meters
  2. Add the length and the width. 25 + 18 = 43
  3. Multiply the result by 2. 2 × 43 = 86
  4. State the final answer with units. The total distance around the garden is 86 meters.

To find the total distance around the rectangular garden, we need to calculate its perimeter. The formula for the perimeter of a rectangle is: Perimeter = 2 × (Length + Width)

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