3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 283 · 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. 1.823 − 223 =
2. 2.613 + 471 =
3. 3.578 + 193 =
4. 4.617 − 201 =
5. 5.452 − 171 =
6. 6.234 + 538 =
7. 7.165 + 235 =
8. 8.195 + 163 =
9. 9.958 − 134 =
10. 10.792 − 498 =
11. 11.507 − 279 =
12. 12.906 − 191 =
13. 13.675 + 321 =
14. 14.528 + 141 =
15. 15.300 + 259 =
16. 16.578 + 651 =
17. 17.576 − 179 =
18. 18.784 − 515 =
19. 19.820 − 546 =
20. 20.701 + 476 =
21. 21.660 + 681 =
22. 22.867 − 281 =
23. 23.589 + 118 =
24. 24.508 − 202 =
25. 25.781 − 326 =
26. 26.521 + 157 =
27. 27.546 + 344 =
28. 28.555 + 564 =
29. 29.290 + 646 =
30. 30.294 + 471 =
31. 31.825 − 127 =
32. 32.698 + 518 =
33. 33.240 + 295 =
34. 34.757 − 609 =
35. 35.556 + 248 =
36. 36.367 + 265 =
37. 37.989 − 456 =
38. 38.864 − 113 =
39. 39.966 − 317 =
40. 40.383 + 555 =

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