3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 958 · 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. 1.608 − 187 =
2. 2.672 + 583 =
3. 3.742 − 197 =
4. 4.631 − 112 =
5. 5.303 + 682 =
6. 6.855 − 212 =
7. 7.686 − 115 =
8. 8.375 + 601 =
9. 9.719 − 412 =
10. 10.448 − 238 =
11. 11.547 + 312 =
12. 12.610 − 333 =
13. 13.434 − 206 =
14. 14.648 + 191 =
15. 15.208 + 342 =
16. 16.615 − 514 =
17. 17.503 − 266 =
18. 18.496 − 371 =
19. 19.478 − 181 =
20. 20.647 − 529 =
21. 21.873 − 481 =
22. 22.236 + 598 =
23. 23.185 + 247 =
24. 24.390 + 205 =
25. 25.738 − 511 =
26. 26.207 + 653 =
27. 27.663 − 493 =
28. 28.471 − 361 =
29. 29.780 − 328 =
30. 30.469 − 218 =
31. 31.516 + 236 =
32. 32.340 + 116 =
33. 33.297 + 605 =
34. 34.785 − 517 =
35. 35.496 + 258 =
36. 36.170 + 204 =
37. 37.887 − 559 =
38. 38.638 − 251 =
39. 39.603 − 141 =
40. 40.510 + 362 =

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