3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 701 · 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. 1.248 + 466 =
2. 2.575 − 131 =
3. 3.542 − 333 =
4. 4.313 + 501 =
5. 5.672 + 121 =
6. 6.420 + 561 =
7. 7.617 − 133 =
8. 8.612 − 139 =
9. 9.635 − 187 =
10. 10.522 + 201 =
11. 11.762 + 619 =
12. 12.508 + 272 =
13. 13.617 + 278 =
14. 14.689 + 648 =
15. 15.204 + 304 =
16. 16.622 + 244 =
17. 17.525 + 455 =
18. 18.500 − 336 =
19. 19.889 − 166 =
20. 20.711 − 356 =
21. 21.738 − 113 =
22. 22.738 − 297 =
23. 23.566 − 148 =
24. 24.313 + 575 =
25. 25.437 − 281 =
26. 26.946 − 302 =
27. 27.232 + 445 =
28. 28.458 + 162 =
29. 29.722 + 176 =
30. 30.645 + 489 =
31. 31.551 + 226 =
32. 32.850 − 394 =
33. 33.426 + 461 =
34. 34.800 − 321 =
35. 35.485 − 288 =
36. 36.812 − 389 =
37. 37.430 − 246 =
38. 38.224 + 389 =
39. 39.915 − 738 =
40. 40.578 − 112 =

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