3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 651 · 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. 1.577 − 341 =
2. 2.476 − 177 =
3. 3.560 + 367 =
4. 4.205 + 119 =
5. 5.665 − 261 =
6. 6.580 − 326 =
7. 7.426 + 151 =
8. 8.648 − 214 =
9. 9.674 − 298 =
10. 10.197 + 455 =
11. 11.687 + 285 =
12. 12.463 − 223 =
13. 13.562 − 418 =
14. 14.389 + 396 =
15. 15.615 + 227 =
16. 16.749 + 289 =
17. 17.633 − 375 =
18. 18.833 − 187 =
19. 19.830 − 241 =
20. 20.558 − 232 =
21. 21.396 + 273 =
22. 22.921 − 569 =
23. 23.137 + 151 =
24. 24.463 − 169 =
25. 25.493 + 276 =
26. 26.620 − 446 =
27. 27.155 + 381 =
28. 28.752 + 161 =
29. 29.773 + 172 =
30. 30.644 + 255 =
31. 31.445 − 219 =
32. 32.720 + 161 =
33. 33.553 − 435 =
34. 34.720 − 481 =
35. 35.877 − 224 =
36. 36.789 − 183 =
37. 37.910 − 733 =
38. 38.737 + 509 =
39. 39.748 + 344 =
40. 40.931 − 299 =

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