Addition
"Add two- and three-digit numbers, with and without regrouping."
A Today you'll learn
- Add two 2-digit or 3-digit numbers without regrouping
- Add numbers with regrouping (carrying over)
- Solve simple word problems using addition
B Let's understand
Addition means putting two or more numbers together to find the total. We always add starting from the ones place, then tens, then hundreds. When the ones add up to 10 or more, we carry 1 over to the tens place — this is called regrouping.
C See it step by step
Example 1: Worked example
- 234 + 125 = 359 (ones: 4+5=9, tens: 3+2=5, hundreds: 2+1=3, no regrouping)
Example 2: Worked example
- 158 + 76 = 234 (ones: 8+6=14, write 4 carry 1; tens: 1+5+7=13, write 3 carry 1; hundreds: 1)
D Your turn
What is 45 + 38?
Look back at "Let's understand" above for a clue.
E Ready to practise?
Always add the ones column first
Always add the ones column first.
If the ones add up to 10 or more
If the ones add up to 10 or more, carry 1 to the tens.
Key idea 3
Line up numbers by place value before adding.
Key idea 4
Addition can be checked by adding in a different order.
Key idea 5
The answer to an addition is called the sum.
Warm up
1. 236 + 143 = ?
2. 458 + 237 = ?
3. 67 + 58 = ?
Practise
4. 320 + 275 = ?
5. 149 + 256 = ?
6. A shop sold 125 pencils on Monday and 148 on Tuesday. How many in total?
Challenge
7. 506 + 289 = ?
8. 72 + 19 = ?
correct
Concepts to revise
1. 236 + 143 = ?
379
2. 458 + 237 = ?
695
3. 67 + 58 = ?
125
4. 320 + 275 = ?
595
5. 149 + 256 = ?
405
6. A shop sold 125 pencils on Monday and 148 on Tuesday. How many in total?
273 pencils
7. 506 + 289 = ?
795
8. 72 + 19 = ?
91