3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 590 · 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. 1.773 + 552 =
2. 2.901 − 677 =
3. 3.734 − 382 =
4. 4.712 − 602 =
5. 5.713 + 345 =
6. 6.574 + 466 =
7. 7.768 − 663 =
8. 8.961 − 536 =
9. 9.934 − 431 =
10. 10.413 − 177 =
11. 11.451 − 231 =
12. 12.504 + 603 =
13. 13.778 + 385 =
14. 14.704 + 487 =
15. 15.641 − 236 =
16. 16.517 − 412 =
17. 17.814 − 665 =
18. 18.217 + 439 =
19. 19.729 − 295 =
20. 20.577 − 113 =
21. 21.789 + 479 =
22. 22.259 + 409 =
23. 23.543 − 145 =
24. 24.842 − 643 =
25. 25.951 − 594 =
26. 26.266 + 471 =
27. 27.703 + 431 =
28. 28.822 − 506 =
29. 29.672 + 247 =
30. 30.749 + 344 =
31. 31.309 + 547 =
32. 32.498 + 571 =
33. 33.543 − 434 =
34. 34.982 − 372 =
35. 35.740 − 265 =
36. 36.571 + 144 =
37. 37.935 − 432 =
38. 38.812 − 173 =
39. 39.781 + 619 =
40. 40.513 + 204 =

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