3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 542 · 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. 1.630 + 296 =
2. 2.865 − 591 =
3. 3.417 − 139 =
4. 4.350 + 229 =
5. 5.564 − 228 =
6. 6.500 + 476 =
7. 7.853 − 171 =
8. 8.152 + 594 =
9. 9.513 − 153 =
10. 10.441 + 552 =
11. 11.597 − 151 =
12. 12.711 − 235 =
13. 13.195 + 135 =
14. 14.935 − 215 =
15. 15.715 + 588 =
16. 16.139 + 237 =
17. 17.347 + 531 =
18. 18.693 − 474 =
19. 19.798 − 371 =
20. 20.395 + 603 =
21. 21.946 − 231 =
22. 22.533 + 181 =
23. 23.513 + 477 =
24. 24.201 + 275 =
25. 25.476 + 156 =
26. 26.487 − 212 =
27. 27.783 + 355 =
28. 28.634 − 488 =
29. 29.766 − 135 =
30. 30.541 + 479 =
31. 31.719 − 467 =
32. 32.597 − 244 =
33. 33.201 + 164 =
34. 34.499 − 311 =
35. 35.739 + 381 =
36. 36.723 − 234 =
37. 37.815 − 432 =
38. 38.520 − 201 =
39. 39.791 − 196 =
40. 40.435 − 151 =

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