3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 372 · 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. 1.560 − 165 =
2. 2.558 − 194 =
3. 3.768 − 418 =
4. 4.950 − 644 =
5. 5.719 − 312 =
6. 6.796 − 502 =
7. 7.794 − 513 =
8. 8.175 + 186 =
9. 9.503 + 301 =
10. 10.430 − 115 =
11. 11.264 + 644 =
12. 12.304 + 186 =
13. 13.671 + 327 =
14. 14.784 − 662 =
15. 15.715 + 528 =
16. 16.542 − 399 =
17. 17.511 − 129 =
18. 18.418 − 293 =
19. 19.626 − 451 =
20. 20.903 − 569 =
21. 21.587 − 207 =
22. 22.908 − 119 =
23. 23.460 + 332 =
24. 24.503 + 351 =
25. 25.487 + 342 =
26. 26.156 + 123 =
27. 27.587 − 473 =
28. 28.304 + 344 =
29. 29.913 − 654 =
30. 30.754 + 155 =
31. 31.324 + 407 =
32. 32.382 + 666 =
33. 33.335 + 164 =
34. 34.436 − 321 =
35. 35.289 + 627 =
36. 36.719 − 505 =
37. 37.491 − 315 =
38. 38.524 − 234 =
39. 39.666 − 446 =
40. 40.464 + 458 =

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