3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 240 · 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. 1.580 − 476 =
2. 2.612 + 462 =
3. 3.514 − 296 =
4. 4.913 − 505 =
5. 5.416 − 188 =
6. 6.207 + 188 =
7. 7.187 + 244 =
8. 8.186 + 125 =
9. 9.201 + 458 =
10. 10.619 − 289 =
11. 11.152 + 425 =
12. 12.433 − 169 =
13. 13.526 − 199 =
14. 14.660 − 556 =
15. 15.695 − 388 =
16. 16.444 − 174 =
17. 17.334 + 434 =
18. 18.312 + 161 =
19. 19.895 − 225 =
20. 20.763 + 662 =
21. 21.677 − 569 =
22. 22.129 + 246 =
23. 23.375 + 152 =
24. 24.989 − 307 =
25. 25.285 + 538 =
26. 26.192 + 133 =
27. 27.778 − 399 =
28. 28.545 + 118 =
29. 29.667 − 467 =
30. 30.745 − 615 =
31. 31.697 − 442 =
32. 32.442 + 497 =
33. 33.850 − 631 =
34. 34.981 − 244 =
35. 35.930 − 141 =
36. 36.573 + 374 =
37. 37.540 − 155 =
38. 38.341 + 295 =
39. 39.466 − 284 =
40. 40.157 + 538 =

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