Three-Digit Addition Worksheet with 20 Problems

Here are the solutions for the three-digit addition problems. I have calculated each one step-by-step to ensure accuracy.

Row 1:
1. $115 + 693$
* Ones: $5 + 3 = 8$
* Tens: $1 + 9 = 10$ (write 0, carry 1)
* Hundreds: $1 + 6 + 1 (\text{carry}) = 8$
* Result: 808

2. $271 + 196$
* Ones: $1 + 6 = 7$
* Tens: $7 + 9 = 16$ (write 6, carry 1)
* Hundreds: $2 + 1 + 1 (\text{carry}) = 4$
* Result: 467

3. $284 + 511$
* Ones: $4 + 1 = 5$
* Tens: $8 + 1 = 9$
* Hundreds: $2 + 5 = 7$
* Result: 795

4. $388 + 205$
* Ones: $8 + 5 = 13$ (write 3, carry 1)
* Tens: $8 + 0 + 1 (\text{carry}) = 9$
* Hundreds: $3 + 2 = 5$
* Result: 593

Row 2:
5. $492 + 162$
* Ones: $2 + 2 = 4$
* Tens: $9 + 6 = 15$ (write 5, carry 1)
* Hundreds: $4 + 1 + 1 (\text{carry}) = 6$
* Result: 654

6. $562 + 411$
* Ones: $2 + 1 = 3$
* Tens: $6 + 1 = 7$
* Hundreds: $5 + 4 = 9$
* Result: 973

7. $464 + 219$
* Ones: $4 + 9 = 13$ (write 3, carry 1)
* Tens: $6 + 1 + 1 (\text{carry}) = 8$
* Hundreds: $4 + 2 = 6$
* Result: 683

8. $481 + 302$
* Ones: $1 + 2 = 3$
* Tens: $8 + 0 = 8$
* Hundreds: $4 + 3 = 7$
* Result: 783

Row 3:
9. $578 + 103$
* Ones: $8 + 3 = 11$ (write 1, carry 1)
* Tens: $7 + 0 + 1 (\text{carry}) = 8$
* Hundreds: $5 + 1 = 6$
* Result: 681

10. $217 + 411$
* Ones: $7 + 1 = 8$
* Tens: $1 + 1 = 2$
* Hundreds: $2 + 4 = 6$
* Result: 628

11. $710 + 108$
* Ones: $0 + 8 = 8$
* Tens: $1 + 0 = 1$
* Hundreds: $7 + 1 = 8$
* Result: 818

12. $295 + 129$
* Ones: $5 + 9 = 14$ (write 4, carry 1)
* Tens: $9 + 2 + 1 (\text{carry}) = 12$ (write 2, carry 1)
* Hundreds: $2 + 1 + 1 (\text{carry}) = 4$
* Result: 424

Row 4:
13. $178 + 102$
* Ones: $8 + 2 = 10$ (write 0, carry 1)
* Tens: $7 + 0 + 1 (\text{carry}) = 8$
* Hundreds: $1 + 1 = 2$
* Result: 280

14. $615 + 638$
* Ones: $5 + 8 = 13$ (write 3, carry 1)
* Tens: $1 + 3 + 1 (\text{carry}) = 5$
* Hundreds: $6 + 6 = 12$
* Result: 1253

15. $209 + 512$
* Ones: $9 + 2 = 11$ (write 1, carry 1)
* Tens: $0 + 1 + 1 (\text{carry}) = 2$
* Hundreds: $2 + 5 = 7$
* Result: 721

16. $670 + 309$
* Ones: $0 + 9 = 9$
* Tens: $7 + 0 = 7$
* Hundreds: $6 + 3 = 9$
* Result: 979

Row 5:
17. $317 + 811$
* Ones: $7 + 1 = 8$
* Tens: $1 + 1 = 2$
* Hundreds: $3 + 8 = 11$
* Result: 1128

18. $369 + 602$
* Ones: $9 + 2 = 11$ (write 1, carry 1)
* Tens: $6 + 0 + 1 (\text{carry}) = 7$
* Hundreds: $3 + 6 = 9$
* Result: 971

19. $237 + 809$
* Ones: $7 + 9 = 16$ (write 6, carry 1)
* Tens: $3 + 0 + 1 (\text{carry}) = 4$
* Hundreds: $2 + 8 = 10$
* Result: 1046

20. $124 + 107$
* Ones: $4 + 7 = 11$ (write 1, carry 1)
* Tens: $2 + 0 + 1 (\text{carry}) = 3$
* Hundreds: $1 + 1 = 2$
* Result: 231

Final Answer:
115 + 693 = 808
271 + 196 = 467
284 + 511 = 795
388 + 205 = 593
492 + 162 = 654
562 + 411 = 973
464 + 219 = 683
481 + 302 = 783
578 + 103 = 681
217 + 411 = 628
710 + 108 = 818
295 + 129 = 424
178 + 102 = 280
615 + 638 = 1253
209 + 512 = 721
670 + 309 = 979
317 + 811 = 1128
369 + 602 = 971
237 + 809 = 1046
124 + 107 = 231