3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 919 · 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. 1.487 − 219 =
2. 2.514 + 688 =
3. 3.138 + 436 =
4. 4.164 + 114 =
5. 5.484 − 291 =
6. 6.186 + 525 =
7. 7.541 − 209 =
8. 8.808 − 491 =
9. 9.849 − 221 =
10. 10.655 − 192 =
11. 11.391 + 233 =
12. 12.768 − 168 =
13. 13.575 + 232 =
14. 14.247 + 223 =
15. 15.476 − 127 =
16. 16.884 − 686 =
17. 17.747 − 515 =
18. 18.281 + 491 =
19. 19.397 + 406 =
20. 20.636 + 623 =
21. 21.914 − 464 =
22. 22.743 − 321 =
23. 23.723 + 557 =
24. 24.705 + 313 =
25. 25.261 + 637 =
26. 26.456 + 281 =
27. 27.613 + 472 =
28. 28.473 − 319 =
29. 29.798 − 663 =
30. 30.592 − 444 =
31. 31.568 + 212 =
32. 32.568 − 238 =
33. 33.860 − 621 =
34. 34.927 − 233 =
35. 35.827 − 727 =
36. 36.517 − 281 =
37. 37.708 + 296 =
38. 38.814 − 653 =
39. 39.687 + 271 =
40. 40.882 − 375 =

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