3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 529 · 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. 1.267 + 462 =
2. 2.793 − 691 =
3. 3.720 − 595 =
4. 4.457 + 662 =
5. 5.985 − 589 =
6. 6.228 + 423 =
7. 7.945 − 433 =
8. 8.606 − 247 =
9. 9.810 − 556 =
10. 10.685 + 368 =
11. 11.169 + 587 =
12. 12.929 − 152 =
13. 13.540 − 376 =
14. 14.167 + 174 =
15. 15.774 + 327 =
16. 16.892 − 445 =
17. 17.522 − 142 =
18. 18.799 − 411 =
19. 19.316 + 591 =
20. 20.790 − 641 =
21. 21.732 + 267 =
22. 22.531 + 182 =
23. 23.689 − 153 =
24. 24.499 + 566 =
25. 25.631 − 438 =
26. 26.834 − 255 =
27. 27.452 − 284 =
28. 28.635 + 128 =
29. 29.466 + 115 =
30. 30.731 + 311 =
31. 31.687 − 394 =
32. 32.746 − 639 =
33. 33.868 − 409 =
34. 34.256 + 379 =
35. 35.644 + 621 =
36. 36.433 − 147 =
37. 37.481 + 381 =
38. 38.524 + 252 =
39. 39.737 + 157 =
40. 40.733 + 587 =

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