3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 280 · 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. 1.970 − 514 =
2. 2.475 − 351 =
3. 3.184 + 627 =
4. 4.377 + 281 =
5. 5.588 + 535 =
6. 6.875 − 561 =
7. 7.613 − 498 =
8. 8.264 + 336 =
9. 9.677 − 213 =
10. 10.641 − 392 =
11. 11.710 − 563 =
12. 12.727 − 226 =
13. 13.775 + 641 =
14. 14.407 + 577 =
15. 15.781 − 209 =
16. 16.468 + 284 =
17. 17.730 − 264 =
18. 18.210 + 308 =
19. 19.561 − 315 =
20. 20.837 − 491 =
21. 21.220 + 205 =
22. 22.238 + 381 =
23. 23.857 − 248 =
24. 24.245 + 199 =
25. 25.934 − 527 =
26. 26.783 + 552 =
27. 27.768 − 667 =
28. 28.538 + 501 =
29. 29.913 − 239 =
30. 30.405 + 113 =
31. 31.625 − 325 =
32. 32.252 + 233 =
33. 33.527 − 118 =
34. 34.147 + 572 =
35. 35.307 + 592 =
36. 36.597 − 147 =
37. 37.526 − 345 =
38. 38.805 − 556 =
39. 39.704 − 417 =
40. 40.363 + 241 =

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