3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 230 · 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. 1.329 + 211 =
2. 2.734 − 141 =
3. 3.672 − 397 =
4. 4.592 + 252 =
5. 5.766 + 135 =
6. 6.453 + 665 =
7. 7.436 + 348 =
8. 8.862 − 413 =
9. 9.678 + 561 =
10. 10.749 − 413 =
11. 11.779 − 473 =
12. 12.488 − 229 =
13. 13.781 − 656 =
14. 14.584 + 201 =
15. 15.593 + 247 =
16. 16.508 + 576 =
17. 17.818 − 342 =
18. 18.658 − 341 =
19. 19.435 − 186 =
20. 20.672 − 345 =
21. 21.525 + 141 =
22. 22.571 − 398 =
23. 23.125 + 156 =
24. 24.724 − 527 =
25. 25.557 − 311 =
26. 26.770 + 594 =
27. 27.223 + 445 =
28. 28.428 − 234 =
29. 29.496 + 539 =
30. 30.129 + 411 =
31. 31.974 − 566 =
32. 32.551 + 464 =
33. 33.449 − 176 =
34. 34.585 − 385 =
35. 35.162 + 155 =
36. 36.847 − 577 =
37. 37.186 + 213 =
38. 38.417 + 451 =
39. 39.461 + 277 =
40. 40.980 − 329 =

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