Year 3 children add numbers with up to three digits, using mental strategies for simpler sums and the column method when numbers get bigger — including carrying.
What your child will learn
- Add ones, tens and hundreds to a three-digit number mentally
- Add two three-digit numbers using the column method
- Carry (regroup) when a column adds up to 10 or more
- Estimate answers and check them
Column addition
Line the numbers up so hundreds, tens and ones are in columns. Add the ones first. If they make 10 or more, the extra ten moves into the tens column. Then add the tens, then the hundreds.
Estimate first
Rounding helps catch mistakes: 298 + 403 is about 300 + 400 = 700, so an answer of 1,101 must be wrong.
Example questions
Here are a few questions like the ones in the first quest. Can you solve them?
1. What is 143 + 16?
- 160
- 259
- 159
- 149
Show answer
Answer: 159. Add the hundreds, then the tens, then the ones: 143 + 16 = 159.
2. What is 216 + 1?
Show answer
Answer: 217. Add the ones first: 6 + 1 = 7. Then 210 + 7 = 217.
3. What is 603 + 30?
- 633
- 733
- 631
- 635
Show answer
Answer: 633. Add the hundreds, then the tens, then the ones: 603 + 30 = 633.
Tips for grown-ups
- Add up shopping receipts together.
- Ask for an estimate before every calculation.
- Use squared paper to keep columns neat.