3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 12 · 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. 1.715 − 373 =
2. 2.882 − 214 =
3. 3.454 − 137 =
4. 4.217 + 461 =
5. 5.636 − 161 =
6. 6.361 + 149 =
7. 7.783 + 535 =
8. 8.277 + 133 =
9. 9.203 + 267 =
10. 10.811 − 502 =
11. 11.800 − 497 =
12. 12.505 + 272 =
13. 13.768 + 344 =
14. 14.287 + 251 =
15. 15.511 − 352 =
16. 16.537 − 136 =
17. 17.464 + 636 =
18. 18.722 + 167 =
19. 19.867 − 358 =
20. 20.508 − 175 =
21. 21.654 − 394 =
22. 22.750 − 288 =
23. 23.682 − 299 =
24. 24.637 − 278 =
25. 25.452 − 274 =
26. 26.266 + 427 =
27. 27.476 + 186 =
28. 28.619 + 185 =
29. 29.750 + 478 =
30. 30.555 + 207 =
31. 31.333 + 376 =
32. 32.207 + 258 =
33. 33.259 + 232 =
34. 34.281 + 177 =
35. 35.480 + 208 =
36. 36.765 + 262 =
37. 37.176 + 354 =
38. 38.450 + 451 =
39. 39.790 − 512 =
40. 40.512 − 313 =

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