3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 941 · 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. 1.694 − 408 =
2. 2.616 − 511 =
3. 3.525 + 651 =
4. 4.724 − 501 =
5. 5.308 + 218 =
6. 6.636 + 663 =
7. 7.443 − 134 =
8. 8.188 + 227 =
9. 9.661 − 165 =
10. 10.228 + 281 =
11. 11.739 − 554 =
12. 12.709 + 268 =
13. 13.576 + 655 =
14. 14.567 − 188 =
15. 15.498 + 113 =
16. 16.279 + 672 =
17. 17.415 + 171 =
18. 18.897 − 301 =
19. 19.763 + 593 =
20. 20.674 − 229 =
21. 21.447 + 467 =
22. 22.345 + 617 =
23. 23.622 − 244 =
24. 24.733 − 532 =
25. 25.357 + 577 =
26. 26.151 + 683 =
27. 27.428 − 191 =
28. 28.454 − 329 =
29. 29.441 − 145 =
30. 30.490 − 221 =
31. 31.582 + 348 =
32. 32.825 − 591 =
33. 33.238 + 331 =
34. 34.196 + 296 =
35. 35.126 + 515 =
36. 36.446 − 178 =
37. 37.671 + 529 =
38. 38.738 − 181 =
39. 39.193 + 275 =
40. 40.736 − 163 =

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