3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 46 · 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. 1.570 + 549 =
2. 2.164 + 609 =
3. 3.771 + 414 =
4. 4.656 − 184 =
5. 5.716 + 143 =
6. 6.277 + 341 =
7. 7.644 − 304 =
8. 8.919 − 465 =
9. 9.270 + 312 =
10. 10.235 + 451 =
11. 11.507 − 301 =
12. 12.470 − 305 =
13. 13.745 + 597 =
14. 14.579 − 443 =
15. 15.545 + 413 =
16. 16.314 + 186 =
17. 17.906 − 264 =
18. 18.286 + 391 =
19. 19.830 − 581 =
20. 20.741 + 147 =
21. 21.496 − 313 =
22. 22.834 − 652 =
23. 23.464 − 229 =
24. 24.787 − 315 =
25. 25.200 + 139 =
26. 26.898 − 341 =
27. 27.498 − 237 =
28. 28.573 − 149 =
29. 29.469 + 385 =
30. 30.726 − 577 =
31. 31.641 − 374 =
32. 32.728 − 293 =
33. 33.572 − 358 =
34. 34.625 + 309 =
35. 35.563 − 121 =
36. 36.883 − 435 =
37. 37.187 + 471 =
38. 38.565 + 656 =
39. 39.734 + 121 =
40. 40.293 + 311 =

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