3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 226 · 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. 1.423 + 216 =
2. 2.786 + 499 =
3. 3.801 − 213 =
4. 4.491 − 141 =
5. 5.144 + 437 =
6. 6.736 + 564 =
7. 7.340 + 279 =
8. 8.522 − 187 =
9. 9.682 − 284 =
10. 10.640 + 499 =
11. 11.603 − 269 =
12. 12.447 − 156 =
13. 13.662 + 346 =
14. 14.505 − 361 =
15. 15.775 + 678 =
16. 16.693 + 352 =
17. 17.468 − 261 =
18. 18.687 − 231 =
19. 19.600 + 269 =
20. 20.298 + 611 =
21. 21.383 + 501 =
22. 22.593 − 375 =
23. 23.951 − 584 =
24. 24.940 − 696 =
25. 25.267 + 284 =
26. 26.466 + 385 =
27. 27.383 + 612 =
28. 28.683 + 501 =
29. 29.616 + 306 =
30. 30.874 − 347 =
31. 31.505 − 257 =
32. 32.589 + 286 =
33. 33.468 − 161 =
34. 34.701 − 442 =
35. 35.322 + 562 =
36. 36.388 + 142 =
37. 37.693 − 325 =
38. 38.653 + 613 =
39. 39.881 − 314 =
40. 40.902 − 381 =

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