3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 987 · 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. 1.404 + 501 =
2. 2.273 + 226 =
3. 3.648 + 639 =
4. 4.860 − 461 =
5. 5.644 − 246 =
6. 6.739 + 583 =
7. 7.558 − 156 =
8. 8.568 − 158 =
9. 9.579 − 382 =
10. 10.502 + 188 =
11. 11.742 − 324 =
12. 12.481 − 375 =
13. 13.722 − 172 =
14. 14.540 − 345 =
15. 15.454 + 573 =
16. 16.589 − 358 =
17. 17.564 − 443 =
18. 18.850 − 563 =
19. 19.504 + 156 =
20. 20.702 + 319 =
21. 21.826 − 642 =
22. 22.596 + 342 =
23. 23.196 + 295 =
24. 24.569 + 319 =
25. 25.504 − 209 =
26. 26.666 − 518 =
27. 27.685 − 508 =
28. 28.758 + 317 =
29. 29.806 − 503 =
30. 30.242 + 611 =
31. 31.906 − 592 =
32. 32.623 + 453 =
33. 33.381 + 312 =
34. 34.454 − 253 =
35. 35.717 + 235 =
36. 36.521 − 358 =
37. 37.580 + 473 =
38. 38.631 − 442 =
39. 39.494 − 304 =
40. 40.943 − 345 =

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