3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 549 · 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. 1.520 − 391 =
2. 2.702 − 228 =
3. 3.127 + 426 =
4. 4.778 − 641 =
5. 5.414 − 148 =
6. 6.402 + 583 =
7. 7.610 − 475 =
8. 8.359 + 461 =
9. 9.179 + 411 =
10. 10.935 − 363 =
11. 11.150 + 548 =
12. 12.506 + 126 =
13. 13.727 + 331 =
14. 14.905 − 691 =
15. 15.447 − 243 =
16. 16.757 + 437 =
17. 17.962 − 187 =
18. 18.455 + 647 =
19. 19.458 − 196 =
20. 20.592 − 241 =
21. 21.481 + 481 =
22. 22.864 − 165 =
23. 23.595 − 457 =
24. 24.335 + 457 =
25. 25.240 + 257 =
26. 26.237 + 564 =
27. 27.444 + 142 =
28. 28.916 − 414 =
29. 29.464 − 131 =
30. 30.664 − 523 =
31. 31.524 − 292 =
32. 32.125 + 619 =
33. 33.325 + 555 =
34. 34.357 + 137 =
35. 35.523 − 264 =
36. 36.819 − 141 =
37. 37.406 + 357 =
38. 38.490 − 217 =
39. 39.772 − 237 =
40. 40.952 − 522 =

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