3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 295 · 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. 1.419 − 206 =
2. 2.582 + 285 =
3. 3.755 − 342 =
4. 4.939 − 703 =
5. 5.264 + 213 =
6. 6.671 − 296 =
7. 7.590 − 475 =
8. 8.860 − 186 =
9. 9.635 − 119 =
10. 10.691 − 454 =
11. 11.862 − 215 =
12. 12.970 − 431 =
13. 13.435 − 261 =
14. 14.409 + 524 =
15. 15.872 − 648 =
16. 16.531 − 297 =
17. 17.470 + 291 =
18. 18.468 + 527 =
19. 19.913 − 661 =
20. 20.680 − 242 =
21. 21.551 + 568 =
22. 22.242 + 347 =
23. 23.673 − 327 =
24. 24.703 + 575 =
25. 25.496 − 197 =
26. 26.369 + 149 =
27. 27.718 + 183 =
28. 28.867 − 583 =
29. 29.369 + 471 =
30. 30.191 + 237 =
31. 31.536 + 336 =
32. 32.463 + 158 =
33. 33.449 + 645 =
34. 34.833 − 723 =
35. 35.766 − 147 =
36. 36.972 − 258 =
37. 37.470 − 271 =
38. 38.434 − 183 =
39. 39.443 − 339 =
40. 40.175 + 293 =

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