3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 305 · 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. 1.549 + 417 =
2. 2.491 − 191 =
3. 3.973 − 847 =
4. 4.893 − 262 =
5. 5.557 + 427 =
6. 6.715 + 389 =
7. 7.309 + 464 =
8. 8.872 − 137 =
9. 9.560 − 213 =
10. 10.559 − 322 =
11. 11.715 + 517 =
12. 12.279 + 268 =
13. 13.981 − 233 =
14. 14.524 + 607 =
15. 15.298 + 662 =
16. 16.804 − 584 =
17. 17.671 + 139 =
18. 18.463 + 255 =
19. 19.536 + 411 =
20. 20.656 − 179 =
21. 21.512 − 266 =
22. 22.384 + 522 =
23. 23.558 + 333 =
24. 24.697 + 685 =
25. 25.776 − 275 =
26. 26.783 − 388 =
27. 27.920 − 345 =
28. 28.521 + 671 =
29. 29.214 + 263 =
30. 30.605 − 424 =
31. 31.223 + 265 =
32. 32.535 + 578 =
33. 33.527 + 152 =
34. 34.522 + 249 =
35. 35.850 − 671 =
36. 36.399 + 525 =
37. 37.498 − 369 =
38. 38.423 − 248 =
39. 39.655 − 394 =
40. 40.207 + 132 =

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