3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 311 · 40 questions

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

1. 1.512 − 241 =
2. 2.679 − 204 =
3. 3.195 + 457 =
4. 4.733 − 166 =
5. 5.763 + 241 =
6. 6.721 − 168 =
7. 7.338 + 345 =
8. 8.828 − 473 =
9. 9.926 − 133 =
10. 10.521 − 412 =
11. 11.460 − 147 =
12. 12.516 − 129 =
13. 13.831 − 483 =
14. 14.751 − 604 =
15. 15.368 + 572 =
16. 16.551 + 252 =
17. 17.514 − 398 =
18. 18.700 + 513 =
19. 19.722 + 402 =
20. 20.705 − 499 =
21. 21.152 + 574 =
22. 22.506 − 347 =
23. 23.433 + 252 =
24. 24.320 + 177 =
25. 25.473 + 669 =
26. 26.305 + 561 =
27. 27.627 − 441 =
28. 28.687 + 667 =
29. 29.695 − 539 =
30. 30.851 − 644 =
31. 31.451 + 247 =
32. 32.224 + 518 =
33. 33.668 − 252 =
34. 34.483 − 181 =
35. 35.607 − 467 =
36. 36.866 − 688 =
37. 37.779 + 205 =
38. 38.187 + 251 =
39. 39.584 − 454 =
40. 40.780 − 301 =

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