Addition of 3-Digit Numbers (Grade 2)
In Class 2, we begin to add 3-digit numbers. Adding 3-digit numbers works the same way as adding 2-digit numbers — we line up the digits by place value and add column by column, starting from the ones place.
We learn addition without regrouping first, then with regrouping (carrying).
What is Addition of 3-Digit Numbers - Class 2 Maths (Addition (Grade 2))?
To add 3-digit numbers:
- Write the numbers one below the other, lining up hundreds, tens, and ones
- Add the ones column first
- Then add the tens column
- Then add the hundreds column
- If any column adds to 10 or more, carry to the next column
Add: Ones → Tens → Hundreds (right to left)
Solved Examples
Example 1: Example 1: Addition Without Carrying
Question: Add 123 + 45.
Think:
| H | T | O |
|---|---|---|
| 1 | 2 | 3 |
| 4 | 5 | |
| 1 | 6 | 8 |
- Ones: 3 + 5 = 8
- Tens: 2 + 4 = 6
- Hundreds: 1 + 0 = 1
Answer: 123 + 45 = 168.
Example 2: Example 2: Adding Two 3-Digit Numbers
Question: Add 132 + 154.
Think:
| H | T | O |
|---|---|---|
| 1 | 3 | 2 |
| 1 | 5 | 4 |
| 2 | 8 | 6 |
- Ones: 2 + 4 = 6
- Tens: 3 + 5 = 8
- Hundreds: 1 + 1 = 2
Answer: 132 + 154 = 286.
Example 3: Example 3: With Carrying in Ones
Question: Add 118 + 45.
Think:
- Ones: 8 + 5 = 13 → write 3, carry 1
- Tens: 1 + 4 + 1 (carry) = 6
- Hundreds: 1
Answer: 118 + 45 = 163.
Example 4: Example 4: With Carrying in Tens
Question: Add 156 + 72.
Think:
- Ones: 6 + 2 = 8
- Tens: 5 + 7 = 12 → write 2, carry 1
- Hundreds: 1 + 0 + 1 (carry) = 2
Answer: 156 + 72 = 228.
Example 5: Example 5: Word Problem
Question: Ria has 125 stickers. Aman gives her 64 more. How many stickers does she have now?
Think:
- 125 + 64
- Ones: 5 + 4 = 9
- Tens: 2 + 6 = 8
- Hundreds: 1
Answer: Ria has 189 stickers.
Example 6: Example 6: Adding to Get 200
Question: What do you add to 138 to get 200?
Think:
- 200 − 138 = ?
- Ones: 0 − 8 → borrow: 10 − 8 = 2
- Tens: 9 − 3 = 6
- Hundreds: 1 − 1 = 0
- Answer: 62
Answer: 138 + 62 = 200.
Example 7: Example 7: Word Problem with Carrying
Question: Priya scored 147 points in Round 1 and 89 points in Round 2. What is her total score?
Think:
- 147 + 89
- Ones: 7 + 9 = 16 → write 6, carry 1
- Tens: 4 + 8 + 1 = 13 → write 3, carry 1
- Hundreds: 1 + 0 + 1 = 2
Answer: Priya's total score is 236.
Key Points to Remember
- Add 3-digit numbers column by column: ones → tens → hundreds.
- Line up the digits by place value before adding.
- If a column adds to 10 or more, write the ones digit and carry 1 to the next column.
- If adding a 3-digit number and a 2-digit number, treat the missing hundreds digit as 0.
- Always start adding from the ones place (right side).
Practice Problems
- Add 124 + 35.
- Add 115 + 142.
- Add 167 + 78.
- Kavi has 130 marbles. He gets 58 more. How many does he have now?
- What is 109 + 91?
- Dev scored 156 in the first test and 89 in the second. Find his total.
Frequently Asked Questions
Q1. How do I add 3-digit numbers?
Write the numbers one below the other, lining up the digits. Add the ones column first, then tens, then hundreds. Carry when a column adds to 10 or more.
Q2. What is carrying in addition?
When digits in a column add up to 10 or more, write the ones digit in that column and carry 1 to the next column on the left.
Q3. Can I add a 3-digit number and a 2-digit number?
Yes. Write the 2-digit number under the tens and ones columns. The hundreds column of the 2-digit number is treated as 0.
Q4. What is the largest sum of two numbers up to 200?
The largest sum possible is 200 + 200 = 400. But in Class 2, most problems stay within smaller ranges.
Q5. Why do we start adding from the ones place?
We start from the ones place so that any carrying is done correctly. If we started from the hundreds, we would not know about carries from the tens and ones.
Q6. How do I check my addition answer?
Use subtraction to check. Subtract one number from the answer and you should get the other number.
