Add 3-digit numbers
On this page children practise adding three-digit numbers including ones, using place-value thinking and checking with estimates. Start with the short method and the examples, then use the online practice or print a worksheet with answers.
How to solve this
- To add three-digit numbers, align ones under ones, tens under tens, hundreds under hundreds, and add column by column from right to left.
- Carry any overflow from ones to tens, and from tens to hundreds.
- Check by swapping the addends (addition is commutative) and re-adding; you should get the same sum.
Examples
347 + 251 = ?
598
428 + 367 = ?
795
Practice problems with answers
Solve these problems on paper or out loud, then check the answer key. The online practice and the printable worksheet give a new set every time.
- 137 + 496 = ___
- 120 + 433 = ___
- 325 + 351 = ___
- 103 + 186 = ___
- 465 + 319 = ___
- 355 + 295 = ___
- 497 + 276 = ___
- 316 + 171 = ___
Show answers
- 633
- 553
- 676
- 289
- 784
- 650
- 773
- 487