3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 153 · 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. 1.580 − 474 =
2. 2.665 + 585 =
3. 3.152 + 178 =
4. 4.542 + 309 =
5. 5.955 − 814 =
6. 6.200 + 174 =
7. 7.520 − 237 =
8. 8.743 − 552 =
9. 9.684 − 271 =
10. 10.403 + 442 =
11. 11.739 + 157 =
12. 12.453 + 646 =
13. 13.669 − 327 =
14. 14.179 + 193 =
15. 15.532 − 281 =
16. 16.836 − 361 =
17. 17.329 + 381 =
18. 18.659 − 192 =
19. 19.872 − 411 =
20. 20.504 − 352 =
21. 21.754 − 359 =
22. 22.264 + 407 =
23. 23.622 + 689 =
24. 24.819 − 685 =
25. 25.692 − 385 =
26. 26.949 − 488 =
27. 27.535 − 304 =
28. 28.739 + 362 =
29. 29.477 + 667 =
30. 30.468 − 352 =
31. 31.798 − 645 =
32. 32.580 − 216 =
33. 33.181 + 261 =
34. 34.747 − 377 =
35. 35.570 − 414 =
36. 36.566 − 186 =
37. 37.678 − 498 =
38. 38.730 + 269 =
39. 39.874 − 393 =
40. 40.452 − 208 =

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