3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 232 · 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. 1.898 − 648 =
2. 2.564 − 268 =
3. 3.381 + 672 =
4. 4.951 − 112 =
5. 5.648 + 297 =
6. 6.595 + 128 =
7. 7.781 + 609 =
8. 8.257 + 389 =
9. 9.469 − 134 =
10. 10.224 + 133 =
11. 11.739 + 162 =
12. 12.695 + 512 =
13. 13.652 + 263 =
14. 14.455 − 191 =
15. 15.577 − 312 =
16. 16.587 − 259 =
17. 17.752 − 222 =
18. 18.896 − 156 =
19. 19.753 + 554 =
20. 20.181 + 361 =
21. 21.329 + 655 =
22. 22.553 − 131 =
23. 23.613 − 238 =
24. 24.404 + 273 =
25. 25.215 + 575 =
26. 26.746 + 481 =
27. 27.334 + 609 =
28. 28.452 − 154 =
29. 29.790 − 506 =
30. 30.397 + 588 =
31. 31.741 − 138 =
32. 32.692 + 403 =
33. 33.581 + 358 =
34. 34.842 − 159 =
35. 35.710 − 574 =
36. 36.465 − 126 =
37. 37.529 − 229 =
38. 38.798 − 356 =
39. 39.972 − 252 =
40. 40.213 + 118 =

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