3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 26 · 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. 1.574 + 483 =
2. 2.426 − 218 =
3. 3.128 + 511 =
4. 4.769 + 648 =
5. 5.277 + 222 =
6. 6.387 + 163 =
7. 7.687 + 611 =
8. 8.320 + 508 =
9. 9.792 − 424 =
10. 10.627 − 201 =
11. 11.576 + 503 =
12. 12.511 − 189 =
13. 13.749 − 281 =
14. 14.345 + 126 =
15. 15.518 − 298 =
16. 16.233 + 507 =
17. 17.399 + 573 =
18. 18.457 − 203 =
19. 19.490 − 326 =
20. 20.933 − 161 =
21. 21.352 + 652 =
22. 22.474 − 325 =
23. 23.906 − 734 =
24. 24.738 + 492 =
25. 25.431 + 151 =
26. 26.285 + 333 =
27. 27.648 − 199 =
28. 28.131 + 295 =
29. 29.907 − 738 =
30. 30.240 + 335 =
31. 31.510 − 293 =
32. 32.893 − 216 =
33. 33.898 − 441 =
34. 34.548 − 274 =
35. 35.915 − 584 =
36. 36.757 − 588 =
37. 37.598 − 137 =
38. 38.488 − 303 =
39. 39.782 + 224 =
40. 40.503 + 402 =

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