3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 570 · 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. 1.697 − 327 =
2. 2.787 − 471 =
3. 3.543 + 125 =
4. 4.460 + 288 =
5. 5.726 − 506 =
6. 6.439 − 145 =
7. 7.702 − 487 =
8. 8.145 + 121 =
9. 9.127 + 172 =
10. 10.874 − 513 =
11. 11.976 − 305 =
12. 12.697 − 117 =
13. 13.909 − 147 =
14. 14.268 + 175 =
15. 15.945 − 823 =
16. 16.535 − 184 =
17. 17.201 + 282 =
18. 18.635 − 311 =
19. 19.765 + 595 =
20. 20.366 + 688 =
21. 21.851 − 133 =
22. 22.417 − 118 =
23. 23.182 + 117 =
24. 24.776 − 507 =
25. 25.907 − 411 =
26. 26.461 + 683 =
27. 27.904 − 769 =
28. 28.890 − 328 =
29. 29.452 + 682 =
30. 30.456 − 213 =
31. 31.221 + 126 =
32. 32.360 + 221 =
33. 33.735 + 118 =
34. 34.805 − 141 =
35. 35.675 + 147 =
36. 36.415 − 197 =
37. 37.610 − 467 =
38. 38.849 − 466 =
39. 39.439 − 221 =
40. 40.220 + 421 =

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