3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 783 · 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. 1.899 − 131 =
2. 2.805 − 479 =
3. 3.802 − 331 =
4. 4.876 − 746 =
5. 5.502 + 469 =
6. 6.763 + 242 =
7. 7.481 + 317 =
8. 8.250 + 261 =
9. 9.331 + 145 =
10. 10.713 − 253 =
11. 11.960 − 207 =
12. 12.424 − 289 =
13. 13.973 − 258 =
14. 14.466 + 636 =
15. 15.530 + 655 =
16. 16.883 − 367 =
17. 17.862 − 231 =
18. 18.164 + 306 =
19. 19.873 − 167 =
20. 20.209 + 639 =
21. 21.487 − 112 =
22. 22.474 − 308 =
23. 23.509 − 198 =
24. 24.825 − 503 =
25. 25.439 − 207 =
26. 26.562 + 345 =
27. 27.310 + 167 =
28. 28.573 + 583 =
29. 29.666 − 123 =
30. 30.439 − 336 =
31. 31.676 + 318 =
32. 32.503 − 122 =
33. 33.430 − 324 =
34. 34.621 + 337 =
35. 35.640 + 634 =
36. 36.614 − 449 =
37. 37.156 + 291 =
38. 38.537 − 142 =
39. 39.438 + 588 =
40. 40.494 + 225 =

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