3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 868 · 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. 1.307 + 519 =
2. 2.286 + 251 =
3. 3.298 + 611 =
4. 4.688 − 295 =
5. 5.878 − 526 =
6. 6.896 − 307 =
7. 7.557 − 167 =
8. 8.636 + 571 =
9. 9.442 + 148 =
10. 10.399 + 306 =
11. 11.197 + 251 =
12. 12.152 + 462 =
13. 13.516 − 256 =
14. 14.808 − 708 =
15. 15.264 + 535 =
16. 16.494 − 163 =
17. 17.424 − 237 =
18. 18.578 − 452 =
19. 19.418 − 304 =
20. 20.423 + 531 =
21. 21.423 − 215 =
22. 22.898 − 741 =
23. 23.462 − 186 =
24. 24.979 − 682 =
25. 25.439 + 656 =
26. 26.501 − 268 =
27. 27.954 − 649 =
28. 28.821 − 565 =
29. 29.638 + 541 =
30. 30.443 − 191 =
31. 31.729 − 173 =
32. 32.988 − 389 =
33. 33.464 − 148 =
34. 34.807 − 429 =
35. 35.675 + 444 =
36. 36.537 + 393 =
37. 37.751 − 359 =
38. 38.514 − 378 =
39. 39.534 + 267 =
40. 40.765 + 246 =

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