3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 767 · 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. 1.559 + 151 =
2. 2.260 + 684 =
3. 3.800 − 311 =
4. 4.459 − 213 =
5. 5.708 − 392 =
6. 6.384 + 518 =
7. 7.605 − 242 =
8. 8.441 + 649 =
9. 9.422 + 262 =
10. 10.507 + 657 =
11. 11.394 + 394 =
12. 12.555 − 119 =
13. 13.819 − 234 =
14. 14.441 + 389 =
15. 15.709 + 464 =
16. 16.746 − 291 =
17. 17.551 + 146 =
18. 18.739 + 561 =
19. 19.642 − 165 =
20. 20.304 + 469 =
21. 21.759 − 354 =
22. 22.260 + 645 =
23. 23.464 − 147 =
24. 24.433 − 298 =
25. 25.898 − 147 =
26. 26.532 − 172 =
27. 27.720 + 523 =
28. 28.616 + 294 =
29. 29.640 − 314 =
30. 30.291 + 671 =
31. 31.652 − 498 =
32. 32.465 − 167 =
33. 33.503 − 141 =
34. 34.574 + 342 =
35. 35.649 − 456 =
36. 36.468 − 261 =
37. 37.756 − 208 =
38. 38.506 + 588 =
39. 39.309 + 355 =
40. 40.469 − 112 =

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